You're speaking for yourself, of course. Unless you can produce some sort of market analisys to back your claims, all you have is anecdotal evidence. For my own personal case, all I really know is that I've been avoiding visual novels like the freaking plague, and I was planning on doing the same for this game, skipping text and watching the sex scenes, until suddenly I found myself trapped by the intriguing story and charming characters.With how limited the audience is and how much actual work it is to write high quality characters, it makes little sense to do that for adult games, and further to answer to a bunch of horny pirates that steal your work anyway. I'd still like to see it of course, but my standards are far lower than what I'd expect in a non-adult game, and I think it's utterly unreasonable to expect any different.
Even if someone had a great idea for something and started that process, I'd only ever take it so far for an adult game, treat it like a demo or proof of concept, then save the rest of it for a mainstream Steam release.
You say it makes no sense, I counter with the fact that the devs managed to charm a determined VN hater into enjoying their game. Evidently, it must make some sense since, to some degree, it works.