These aren't exclusive camps, y'know. If all you want is sex, then the internet has loads of sex- if all you want is adventure, then the internet has loads of adventure games- it's rare to find a game that links those things. A lot of the lewd games pouring out onto Patreon right now play like incredibly linear, non-interactive stories, or incredibly dry number games that are only lewd on a surface level. "You have three rounds of sex today, and cum this exact number of times. You gained this much experience in this, this, and this." Visual novels, and management games seem to be the easiest to produce, so they're just all over the place.
People draw lewds of video game characters from completely family-friendly franchises for a reason. They get invested in the adventure, the world, the characters, it satisfies a lot of appetites for them, while pointedly avoiding any adult themes or ideas. But they're immersed enough that when they start feeling those appetites and desires, they look to those games, and their characters anyway. Peach ain't flauntin' her body for anyone. Zelda's never shown much skin in any game. Hex Maniac had a handful of brief appearances, and none of those appearances were in any way adult, unless you imagine the milk she's selling is something else.
Yes, there are times when all someone wants is to stick pipe a, into slot b, but if that's what they're after, they'll choose a different, much simpler game that doesn't involve all the combat, exploration, and grinding to get those scenes. Or they'll just a watch a video. Or look at the ever growing mountain of images piling up everywhere. If they want simple, and straight-forward, it's being dished out, there's no lack of it. What makes CoC, CoCII, and TiTS stand out from the crowd is that they're- at least on the surface- "something more". They're offering more investment. They're offering more to do, see, experience, and giving the player some small amount of say in things, while still satisfying those adult appetites. More investment, for bigger pay-offs.
That's why Fenoxo and his crew have to promise things like story development in the first place, why they won't ever risk saying something like "Sorry, we're not bothering with anything but user-submitted donation-fueled content from now on-", people would completely lose hope. Lots of people don't want to watch Game of Thrones now that it's finished, because the ending ended up being a huge disappointment, so why get invested? Same sort of deal here. They can still get people invested, eeeeven if it's just by stringing them along...
If you want to argue that the faith is misplaced, that's a whole different thing, though. I go back and forth a lot. I want to believe something amazing'll come out of this, but.. They sure don't seem passionate about working on any of these projects. They talk about each update like disillusioned door-to-door salesmen, forcing enthusiasm, and tossing in half-hearted sales pitches, but just not feeling it anymore. Peddling smut they can't even fap to anymore.