Though I think the best and long-term solution is to just create a web framework that allows people to self host their games while also providing payment options without having to implement that stuff manually.
Like I said earlier, I don't think porn games will go away. They have always been niche and most of them were self-hosted for this very reason. Games like Sociolotron required you to purchase the game directly from their website. Other games were purchased via mail-order. I think we will simply go back to the former.