My wife studied costume design with a focus on historical European garments a few years back. Fascinating field!
And yes, when you can't mass produce clothing it goes up in price massively. Most mass produced clothing costs slightly more than the fabric, but even a very fast couturier will spend hours on a single piece. On top of that, it's one of those industries where price sensitivity inverts at the upper end.
Custom clothing is used to signal wealth, so past a certain point, more expensive actually becomes more desirable.
It happens when something is supply constrained and a costly signal. Universities are the classic example, Harvard would never lower its prices to be more appealing than Yale.
Well, obviously there's an upper limit to that game, but I would bet Princeton's issue wasn't that they were failing to fill classrooms at the higher price point.
Harvard’s signal is how hard it is to get in. There are less prestigious universities with a higher sticker price. Bad example, but I agree with your point in general.
Apparently further beyond "Veblen", price stops being a signal because the very wealthy have money. The signal has to change to other more scarce resources: https://news.ycombinator.com/item?id=47265889
Suppliers will often sponsor/partner with high-profile athletes, providing kit for free and treating it as an advertising expense. Still "pricey", but accounted in a different way.
The Turner Twins website has sections on their – fairly significant – PR/Media work and Brand Partnerships.
"Dear Mother: school is fine. I'm getting good grades. Please send money for a new tunic, as I have torn my only one. Love, John" - gist of an actual 15th-century letter home from a university student.
Must be pricey.