But why pay when there is redtube and the rest?
And why would you need to pay, when in fact the porn ecosystem is as follows:
- Group A produce porn to a high quality (technically: the scripts usually leave something to be desired) using the bottomless pool of desperate young women often with drug problems who think that it's a way of getting into Hollywood. They sell this to people who want new material in fullHD which fulfils the precise details of their niche interests. There's still a perfectly decent market in making for-money porn, although it's not as big as it way. Their product is either very pretty young women having relatively (I say, relatively) non-abusive sex in expensive houses in the Hollywood Hill, or a declining spiral of progressively less young and less pretty women having progressively more abusive sex in progressively nastier locations.
- Group A accept that their customers will rip the content off and upload to video sharing sites. Those sites, let's call them Group B, make their money out of selling advertising space, both for the for-money porn in point 1 and for general advertisers, with a different balance between those for youtube on the one hand and (let's not name them).com on the other. If Group A's customers rip off either their latest stuff, or rip it off in too high a quality, Group A issue Group B with a DMCA takedown notice, which will be immediately actioned. Group B have robust and effective mechanisms to deal with illegal content and reported copyright violation, because they are not remotely interested in porn; they are interested in making money, and therefore any legal challenge will ruin their entire business.
So Group A make money by selling HD porn, and Group B make money from advertising sales on the back of low-res porn (and some "premium memberships", but their heart isn't really in it).
Meanwhile, a whole load of home-made stuff is being made by Group C, presumably (I'm guessing) semi-consensual, although you can't help suspecting it's the hallmark of an abusive relationship as well. The producers aren't interested in making money, but Group B is quite happy to host and stream it, because they can sell adverts on it anyway. Group C don't have quite the same need to stay legal, because they're hard to find and don't keep accounts, but Group B still doesn't want to host illegal material, because it will get them closed down and turn off the magic money tree.
Groups A, B and C are adults and their material is mostly legal in most places. The UK CPS has occasional fits over, oh, let's not mention that, and, oh, let's not mention that, both of which are perfectly legal to do in the UK but in principle illegal to make videos of, but in practice anything involving adults who are not being immediately and actively harmed will not excite (ho ho) the law. There's a political and ethical question as to the reality of the consent, but the same might be said of all sorts of things. No-one rational thinks this should be made illegal, and even few people think it would be possible so to do.
And finally, the really, really nasty people who either are interested in illegal material or are sufficiently keen to make money that they will risk illegal material are operating on the dark Internet, far from any observation by Google. Groups A, B and C will run a mile from child porn, for example, because there's not enough money in it to risk the jail time and (in their own eyes, at least) they are mostly decent people whose response is of revulsion just the same as the rest of us. Every study shows that there is little to no straightforwardly illegal material on the public internet; it's all being traded on the dark internet, and if you "solved" that, they'll just get better at encryption (they're not bad at it already).
So A are happy to see their stuff given away provided enough people pay, B and C are giving it away, D you never come into contact with. It's a functioning economy.