I think you are underestimating DPC's drive and determination. The man is an absolute machine when it comes to his projects. And I wouldn't limit his options to just a less pornographic VN. I'm thinking something more along the lines of an actual video game (if he creates an indie co), something without the constraints of visual novels or even Renpy. AL and BaDIK are his personal projects so he doesn't want or need any assistance, but if he wants to hit the big time, then an indie company is the way to go.
DPC has a rabid fanbase that will follow him to the end no matter what he does next, PG, R, or X. If Icstor can retain thousands of Patreon cows without providing anything, then DPC will certainly keep the majority of his fans after BaDIK. That Patreon/Steam money train is never going to stop running.
DPC could easily be improving animations and render quality not only for BaDIK, but as practice for his next mainstream game. These skills are quite transferrable to the non-porn market. And let us not forget his mini games and filler. If that doesn't scream mainstream, I don't know what does.
But I think part of the desire to switch markets is ego driven and another part is to constantly improve his work.
DPC has an ego and this is not necessarily a bad thing. Ego can be a catalyst for improvement. I believe he wants (and maybe even needs) more mainstream recognition. That kind of thing can be intoxicating to someone who was a nobody just a few years ago. I don't think he wants to be known for the rest of his life as a porn game dev. He certainly seems almost giddy when prominent mainstream youtubers and such take a liking to his games.
Regarding the desire to improve, DPC has already mastered the AVN market. Like the great commanders of old, the best are always looking to conquer new territory. There is little more DPC can do with AVNs and he has talked about making sure he does everything he wants to do with BaDIK before moving on to the next game. Another AVN would just be BaDIK with a new skin. I think he is eager to challenge himself outside of AVN world.