Responding to UF here, but these comments are general:
One of the things I don't think most people have a handle on is that writing is very, very time-consuming. They may know that intellectually, but it immediately gets lost once something is presented. The result is that people look at a piece of plot/writing, and ignore or fail to recognize how much time it would require to take things in any given direction. That's particularly the case for something like a VN which could easily branch in a way that is difficult or awkward to keep from expanding out of control.
My point is that community/fan input is, no doubt, a factor because writers don't live in a void, and input influences output just by contact/dissolution. However, I think people play up like that's the basis of the decision making. The reality is much more likely that the beginning was nothing more than an outline, and as the writing progressed it went in different directions, trailed off in some, and wound up where it is now simply because it's a multi-year work in progress, and things changed as they went along. With the benefit (or, in this case, the hindrance) of hindsight, members of the audience look at the development process and see a shifting plot/story elements, and they want to attribute that to general things like an abstract concept of market forces which is, as mentioned, is a factor, but even with an outline in place, things go their own direction when a writer sits down to do the job.
It's more likely that he just changed his mind, found certain plots/subplots too elaborate or dead ends, and went along the writerly plot path of least resistance. That's how a work-in-progress works and progresses. This is a porn VN so, of course, people focus on the fetishistic content, but there was going to be some "choose F's job" option in chapter 1 too that's pretty well dropped. Why? Because it'd be a pain in the ass to implement certainly, and not worth the effort. Similarly, any of the villains that get introduced could be more along the lines of recurring characters, but why bother? Is that how the VN should progress? Maybe. But more than likely it's just too much time, effort, and maybe didn't work well plot-wise, meaning it would branch the story in a way that wasn't easily brought back on track. In practice, it just didn't work out that way.