Ah, that's right. I can't remember for sure, but I think that was right around the time Patreon hired the Puritan Police and incest became verboten. At that point, I wonder if the dev decided that the game couldn't even be reworked, given the heavy focus on incest. That's a random guess, though, because titles like this one and F.I.L.F. clearly are written in such a way that it's possible (even if "officially" there isn't any).
It's been forever since IC in Paradise, so I can't even remember anymore really. But given it's the follow-up to Incest Adventure and The Artifact (both of which were solidly incest games) and part of the premise of IC in Paradise was that the incest continued with the same two families... yeah, I'm fairly confident the anti-incest Patreon shift sank that, since the dev would potentially get shut down for continuing it. Although, strictly speaking, nowadays he could always add a Subscribestar account and then finish IC in Paradise as an exclusive over there if he wanted. But at this point, I'm not sure he'd have the desire to return to it.