For better, for worse: Who really cares about the royal wedding?

I'm working on the day. Out there, facing the Palace in a media Portakabin. I'm doing the BBC World Service, meaning it must go everywhere. And I imagine I'll know what I think of it all by then, whereas I'm still all over the place now. They come across as nice enough, the royal couple (though she seemed much more frightened in that first TV interview with Tom Bradby than the widespread view of her as little Miss Calculating Congeniality would suggest). And the Palace can certainly put on a do. We're undisputed world leaders in mounting a certain kind of royal event and telling people about it, and if you've been reading newspapers from the Anglosphere – the US, Canada, Australia, NZ – you'd see that it was really working.

They clearly love it. People are interested and engaged as they would only otherwise be in a hyper-A celebrity event. Only more so, because the combination of attractive young people and British royalty means a special celebrity-for-life status. Completely unlike the Hello! crowd, the sashed and medalled operetta Euro-royalty, who play like 19th-century residuals in American media-land (there wasn't exactly much external coverage for the Swedish princess who married her personal trainer recently).

The interest goes wider than the Anglosphere, of course. To India and the rest of the non-Anglo Commonwealth. And the rest of the BRICs too. Everywhere but here. It'll be all right on the day, naturally. People who've been loudly telegraphing their sophisticated underwhelmed response, people who've said they'd rather be in Uzbekistan on the day, will actually turn on the telly at 11am this Friday.

There are a million excuses when it happens, of which some kind of zeitgeist-checking, post-modern, social cohesion thing will be the first. The clever-dick intelligentsia will want to be in on it, because it's one very long watercooler moment and intellectuals are supposed to share popular culture now – not like those 1960s philosophers who proudly didn't have a telly.

Guardian columnists and even the nation's little happy band of convinced republicans (see feature, page 18) will want to have watched the key moments. They'll want to have copped the aesthetic, seen The Dress and heard the vows – in real time. They'll want to have something to say later. The world TV ratings – though not in the Charles and Di league – will be bigger than anything royal since then.

The street party response has been disappointing – many fewer than 1981 and a more markedly southern retro- flavour to those that are planned. But 1981 was practically BC in terms of the changes to the kinds of communities that have street parties – company towns, motor towns, mining villages, the lot. After all, 1981 was the year of the Specials' "Ghost Town" and every famous riot going, but there were still communities to fight for. Now it's all grassed over for Call Centre and Office Park Britain. Gone. How could you expect cheery knees-ups everywhere?

Gone, too, is the un-metropolitan hinterland of habit and hierarchy that made a major royal wedding so oddly powerful – especially when it was divisive – because it reflected some underlying truths about class and, to use an accurate word that now sounds completely archaic, degree.

Back in the early 1980s, you could still see glimpses of where power really lay. During the Falklands War, the veil of drabbed-down media accents was lifted, the froth blown away. We were seeing and hearing military men and Chatham House strategists and backwoods Tories every night. A genuinely powerful group who all spoke ringing Received Pronunciation or better. That was all still around. Also in 1982, Ann Barr and I brought out the first Sloane Ranger Handbook, which described an upper-middle-class world still astonishingly, privately, in place. Tim-Nice-But-Dim (actually Harry Enfield's later 1980s' creation, mocking a hopeless has-been) was still just getting by, holding down a job, drinking at The Antelope.

Successive waves of new money since then have done more to change that rooted world than any amount of post-war socialist legislation or high taxation. All kinds of new money, at every level, from every source – and much of it clever rather than crass – but made at such a rate that everything changed, swept before it. The change in the social order paralleled the change in the British business base – the brutal de-industrialisation. For a while, many people didn't notice; for a while, home-grown New Money liked simply to take on the style, the protective colouring, of the Old. (We were probably part of this; a lot of 1980s people saw the Sloane Ranger Handbook as a serious guide to life.) But Big New Money didn't live the life, it just bought it up.

The hugely increased importance of the post-Big Bang City in our national life only exaggerated the importance of London – the monstrous Wen – and its service economy more generally. The popular imagery of the City, for ages afterwards, was about West End Boys and East End Roughs who shouted a lot. The reality was duller, but more corrosive. Great tranches of the City – especially the "casino" banks – actually had American, Japanese, German and Swiss owners. Hyper-educated foreigners – people for whom the nuanced world around the royal family was decorative but irrelevant – ran the show on a visiting fireman basis from gated communities such as Holland Park or the new Thameside high-design blocks. And for East End boys, increasingly read geeky "quants" with maths PhDs who could do super-sums (the kind Gillian Tett describes in her book, Fool's Gold). The world of county families and Lords Lieutenant didn't figure at all.

All this meant the System, the Form, everything that still supported and drew support from the monarchy as a symbol of social order in 1981 was hollowed out by 2011. What had replaced it was the crust, the gratin of the global super-rich that now dominates Big London. New Money that has cherry-picked the signs and symbols and stuff of the old elites, but doesn't reference them in any way. Those people don't want to do what earlier – home-grown – New Money ached to do, which was to assimilate (move north to south, acquire titles, acres and old houses and mulch down). If an earlier, local social mobility – 1970s education and game-raising – developed families such as Kate Middleton's, people who typically run new kinds of businesses from old houses, then the New World Order did the rest.

When the rich lists started in the late 1980s, they still seemed dominated by inherited money – aristocratic, plutocratic and royal. By a sort of assimilated consensus class. Now it's unrecognisable – the serious money is "New" and global and fragmented across styles and segments, with royal money severely demoted down the list (though, of course, royal advisers prefer it that way, and comfortable aristocrats would usually rather not have the attention either).

What sociologists call our "reference groups" have changed. For the UK over-class, it's their global-rich peers (they compare themselves to Wall Street, Silicon Valley or Shanghai). And for the uniquely durable British underclass, it's Lottery winners, football players and entertainers, people in the low-end celebrity press, Fickle Fingers of Fate people. To stay relevant, royal people and styles have both to acknowledge all this, yet still stay aloof from it.

This royal wedding acknowledges the new world in Kate Middleton's very polished global kind of prettiness, so different from Princess Diana's brilliant-but-British-barmy early styles. It stays aloof in Prince William's completely traditional job as a serving soldier. But strangely when they're together – and I completely believe in their relationship – they look that bit like a pair of nicely spoken TV anchors doing a sort of national tour-guide job.

There's a big economic and political sub-text here too, of course. The economic argument says that it's all good, cheap advertising for the UK. We'll be in billions of houses around the world. With people who barely know the UK exists any more, except for Premier League football. And that has to be good, so the argument goes. It'll provoke tourism and inward investment and skilled immigrants – the ones k we really want. The evidence is hazy on all of this. There's no clear tourism spike apparently. And inward investment is pretty difficult to attribute to this kind of event too. But it might just help another Mrs Global Plutocrat decide that she should have a Mayfair house as well as a Zurich one and a New York apartment.

We don't really know what royal weddings do for our national brand, but some analysts believe that anything like this helps confirm the idea of the UK as Fantasy Island – charming, archaic, undynamic and class-ridden. It's one that comes up persistently in the Government's various global research projects. Does that really matter? At least we're distinctive, you might think.

The domestic political agenda lies in the idea that it'll take our minds off the cuts and give us a feeling of well-being – a generalised glow of national pride in our charming, archaic etc culture. Something that shows up in David Cameron's happiness index and, possibly, in elections. Cameron reportedly banged the Cabinet table when he announced the royal engagement last November and said something about it being "a piece of unadulterated good news". (Then again, as a teenager, he'd slept out in London to ensure his front-row view of the 1981 wedding.) But if we really are now treating royal people and events as a sort of Grade-I-listed variant of celebrity, then the "tonic for the nation" effect may not last long. Our celebrities usually don't.

When Olivia Stewart-Liberty and I were writing Cooler, Faster, More Expensive – our 21st-century update of the Sloane Ranger Handbook – we were constantly asked whether Kate Middleton could really be a Sloane, given her background. It was a nasty, snobbish question that left us feeling squeamish. It was probably hurtful to her and her parents. And the real answer was that someone with her immediate background – smart education, Home Counties, high income – who was prepared to sign up to a pretty limiting world view could perfectly well be a Sloane if they wanted to. And the whole "doors to manual" thing that some of the brothers' friends went in for (in reference to her mother's former job as an air stewardess) was awful (and they'll be sorry now).

A lot of this prurient harping on about the Middletons' background came from London journalists who are more concerned with all that, the Milk In First imperatives, than almost anyone else cares to be – including, obviously, Prince William. Last week, Channel 4 ran a have-it-both-ways programme, which looked at the Middleton family across the generations. There was a great range of people involved, from Northern upper-middles to moved-out East End working class, often with pretty distant relationships. And a story of post-war social mobility that was actually much more typical of the baby-boomer world than the film-makers seemed prepared to admit. And now that, as we know, English public schools have masses of chancers' sons and Chinese plutocrats' daughters, Kate Middleton is pretty mainstream (even if life really was as tough for her at Downe House 15 years ago as some stories have suggested).

Perhaps the most disturbing story was one in the Daily Mail recently, which described how Kate was being groomed for her new role, being taught to dress the part of a Royal Lady. "They", whoever they are, seemed to be suppressing all the pretty new mainstream Sloane things that people like about her – the nice loose chocolate-coloured hair (that bit Anne Hathaway) and the mainstream wardrobe (part smart brands and New Sloane specialists like the elegant Katherine Hooker, part high street). They wanted, according to the Mail, to replace her style with ageing royal workwear – hair up, longer skirts, solid heels on shoes. The world of the weighted hem, where royal clothes are symbolic yet oddly utilitarian and observe priorities and constraints practically no one else suffers. These are clothes with what a costume academic, describing the Queen's 1947 wedding dress on TV recently, called "an agenda".

But Kate Middleton's family back-story and her pretty identifiable, aspirational just-modern-enough look are huge advantages in the job of updating the Firm (Americans call it "contemporising"). It'd be perverse – bad branding – to try to move her back to a sort of Stepford Wife look, just as it seems perverse for a young graduate not to have had a job before her marriage. Her female contemporaries at Marlborough will have had real career ambitions – and of course, understanding the extraordinary changes in the working lives and expectations of women is pretty much the start point for understanding the modern world.

But the process – the taking and changing of the bride-to-be, if it's really happening – is more than bad judgement and poor branding. It sounds spooky, in an Of Human Bondage way. As if the Firm's culture is still to try to make people into People Like Us despite all the awful warnings of the past. You obviously do need some vocational training to be a Royal Person. Apparently the Queen Mother did it for an earlier generation, teaching them how to make conversation – keep to flowers, dogs and travel distances; avoid difficult subjects, like religion, art, politics and human beings generally. Keep Smiling.

There may be a feeling that earlier royal ladies from "outside" – Diana, Fergie, Sophie – weren't helped or "trained" enough. It was all so much easier in the 1890s, marrying German princesses who knew The Form. But mightn't the lesson be that the late-20th-century royal form was so very odd that most people didn't get it – including Diana Spencer, a hyper-aristocrat by any standards? Then again, there's Prince William's evident concern – and with reason – to protect Kate, now officially Catherine, from all that. From bullying, unwelcome attention and a weird life. And it may yet work out – their St Andrews life worked out well – and most people will be glad if it does.

Johann Hari argued recently in The Independent on Sunday's sister daily paper for the republican option as an altogether fairer and more rational way to run a country. But it doesn't look like a particularly popular option, either for the people – as reported in polls – or for politicians. All three party leaders obviously consider any hint of republicanism a don't-go-there position. And a friend who writes in another broadsheet is convinced he'll have to go to a little political magazine if he wants to get his republican rant published at all.

But the general uprooting of the old royal idea and its hinterland means the royal family is increasingly seen as a political convenience, to distract, cheer up and publicise parts of the ruling party's grand strategy. It's difficult and it's compromising for the Firm. But what else can they do?

In the meanwhile, they have to make a go of it. The event has to be just sentimental enough (without anything Vulgar! Vulgar! Vulgar!), just grand enough (cheeseparing restraint is pointless, because they'll get it in the neck from their critics anyway, while the world and his wife will be disappointed) and just modern enough. The obligatory Hello! royals and worthies aside, they need enough house-trained Lily Allens and James McAvoys among the guests to show membership of the mainstream Hollywood-friendly new world of late twentysomethings. And they need to be very careful about the Middle East; it's a minefield now – both in terms of wedding guests and holiday venues. The nation doesn't like Middle Eastern and Eastern European dictators any more than it likes the Taliban. The Prince Andrew set didn't play well.

The author and critic AA Gill tells me that he sees that Human Bondage aspect of royal life as the big problem now. The royal family, he thinks, is caught in a trap of their own making. It is duty and self-interest, habit and romance, but, according to him, it distorts their lives out of shape. And they don't have to go on with it. They're frightened of freedom, he suggests, in the same way animals kept in cages fear it – and perhaps what needs to happen is something along Joy Adamson lines. The royal family needs to be taken to a Born Free kind of break-for-the-border spot – with a view of the great plains below – and told kindly, "You're free to go."