Well, I'm not sure. If you walk into the porn section of any video store, you don't see much on fetishes at all, but a hell of a lot on straight, in your face sex, sometimes with a little story around it. Content irrelevant, as long as they get on with the job of screwing.
In Europe, a lot of the quite standard brothels offer 1 room for BDSM, and in each town there are some mistresses who specialise. But that is a small fraction of the population, or those places would be flooded and spring up all over. Same thing with what the prostitutes offer in Europe. Most of them offer fetish content, and are obviously versed in the fact that it exists, and there are clubs around where you can take a partner, but widespread?! Really not sure.
I think that for many people just being into one another is a turn-on, and then they begin to experiment on what works for them. The need for fantasies and fetishes is, I believe, particularly relevant for those who use these for masturbation.