NEW YORK, United States — The explosion of the global luxury market over the last decade has rewarded its top players handsomely — the margins on a $1,500 T-shirt or a $170 paperclip can be quite generous. But the growth in the market raises a question about what it means for an item to be luxury: Is it exclusive? Is it truly luxe? Or is it just expensive?
Dita, an eyewear brand more than two decades old, is testing the limits of the…