I have my own theory to explain the differences between the way that fashion models look (esp the "elite" NewYork/Paris ones) versus the sorts of models you see on the covers of men's magazines. My primary theory is that the former are chosen mostly by women and gay men. Whereas the latter are chosen mostly by straight men. Notice how much more boy-ish, angular and bulimic fashion models look compared to the women you see in Maxim or Playboy. The former are chosen more to show off clothing whereas the latter are chosen to show off themselves.

So big differences both in purpose and in the controlling audience.