Counter argument:

The more places ban nudity the more chance the one site that allows it becomes a porn site.

Currently if you want to post artistic nude you pretty much need to do it on a porn site.

The opposite may also be true, if more places accepted it then the amount of nsfw content spreads out, there might be more porn sites overall but with more incentives to specialize and innovate rather then allowing almost all of it and knowing users will come regardless.

Is it ripe for harvest time yet?