About two years ago I had lunch with François-Henri Pinault, the chief executive of Pinault-Printemps-Redoute, the French conglomerate that owns Gucci Group, and he told me he thought we were deep in an age of irrationality, governed by emotions and desire. This was a good thing for the luxury industry, because luxury products are unnecessary products, and thus the motivating factor in their consumption is not logic, but sheer, stomach-wrenching want.

Pinault thought this giving-in-to-the-id was going to go on for a while, and he wasn't alone: when I used to talk to fashion executives about how long they could keep opening new stores, the answer was almost always, "We can't see the end". And though you could say that was a line, I honestly believe they believed. Still, things have changed, and recently I've had more industry e-mails that talk of, or around, the return of "rationality" than there are gold zips in a Gucci store.