That only happens if your main motivation for making the game is Patreon bucks. And that pretty much guarantees burnout and a shitty result. If you started making a game just because...you wanted to make a game, the Patreon plateau means jack shit. You have a creative block, you temporarily close the Patreon and take your time. But that can't happen when you gotta have them keep paying no matter what.
People seem to forget that erotic games existed before Patreon, just fewer. But what used to be a simple paypal donation from someone who appreciated your hobby, became a steady income stream via subscription model. And the incentives changed, attracting new people who came in with dollar signs on their eyes. That's the very reason you see the never-ending behemoths you mentioned. There is obvious incentive to keep the stream going as long as possible.
It's pretty much what happened to the mainstream gaming industry, just on a much smaller scale and with more amateur practices.