Well, I can't say these are the *only* ones I've found that do that, but they're the only ones that weren't a quarter-completed before being abandoned, or were more along the lines of "good ideas with horrible execution". Even then, among these four games, HHS never really got past beta and the latest version of SimBro is currently caught in between platform changes, and looks to be badly hung up besides. Only this game and SM can be considered real A-list material.
Although, if you're into that sort of thing, there are several very decent dating sims out there as well. SimGirl, although never finished, was moderately good - so was Ganguru Girl. Of course, you also have to name Date Ariane as very good, and there are another two or three dating sims off Newgrounds that meet my standards as well. Still, in the main you're quite right - the quality level for this sort of thing is pretty abysmal. Lots of potential game makers take their cue from the professionals, and make the quasi-linear story type games; that's fine if you have a good writer and a better artist, but even the professionals miss on those half the time, meaning that the amateurs generally do much worse. It seems like most of the creators either lack creativity, or skill, or all-to-often both.
If, however, you aren't explicitly looking for hentai, you should take a glance at the Adult Interactive Fiction (AIF) community. It's been around a *lot* longer than anybody else, and while a good part of those works don't have any pictures there are some that are very, very good in that regard too.
