Alexander Fury: Fashion's musical chairs are fun to watch, but not very edifying

So, Marc Jacobs has left Louis Vuitton, after a blockbuster 16 years. In a quieter fashion, his almost-namesake Marco Zanini bowed out of Rochas to head up the relaunched Schiaparelli. J W Anderson was appointed creative director of Loewe. And on the final day Paris began to buzz with news of the revival of the age-old house of Jean Patou.

It's all terribly confusing, these games of designer musical chairs. It also reminds one a little of the late 1990s, when Jacobs was first installed at Vuitton, hot on the heels of the appointments of McQueen to Givenchy and Galliano to Dior. They were showmen with an urge to dazzle and delight. The demands of fashion have changed. The idea of fashion for fashion's sake – or, perhaps, beauty for beauty's sake, to borrow a phrase from the Louis Vuitton show-notes, written by Marc Jacobs himself – isn't enough. Designers aren't just expected to bump up a brand's image, but to garner positive reviews and send sales figures sky-rocketing. If they don't, the doors will revolve again.

They can revolve dramatically: the house of Emanuel Ungaro has employed everyone from Giles Deacon to Lindsay Lohan (yes, really).

It even had Peter Dundas, for all of three seasons. He's since hit commercial paydirt with a spectacular revival of Emilio Pucci. Why didn't Ungaro work?

The issue is two-fold. Firstly, every designer doesn't fit every house. I am an enormous fan of Zanini, but I'm not convinced he's the right man for Schiap. Many expressed the same thoughts over Alexander Wang's appointment at Balenciaga, while Hedi Slimane's heavy-handed reworking of Saint Laurent, from the logo down, has caused controversy.

The other issue is of longevity. Designers seem to be chewed up and spat out before they have chance to warm their seat, let alone get their feet under the table. Fast fashion may be all the rage on the high-street, but it doesn't really work at this level. Bide your time. Let them grow.