BTW, I happen to think that stretch of Fifth in the fifties to be nearly unbearable. I don't consider that area a great retail area, however so it is such historically.
The decline of Fifth Avenue (and midtown) as a premier shopping district has been well documented, but it still holds its own and attracts premier stores. Yes, pedestrian chain stores such as Banana and GAP dominate, but Pucci and Bottega Veneta opened brand new flagship stores just last year (BV coming from Madison Ave), and Ferragamo and Zegna both moved into fancy new digs. It used to be that the closer to 57th, the more upscale the store was, but Abercrombie (sadly) is setting up shop in the old Fendi space on 56th, next to Prada (I believe Fendi is relocating to the opposite side of the street). The foot traffic on Fifth is what's unbearable, but it is what appeals to mass market retailers that have come to redefine the Avenue. As for the the location of Berluti, I think it's perfect. I'm sure rents north of 72nd are lower, but the clientele needed to make the store a success will know it's there. They aren't relying on the average tourists for business and don't need a high profile location. Plus, Upper Madison isn't exactly lacking, with Vera Wang, Michael Kors and Missoni all within reach.