To try and honestly answer the question of why 3D games seem to be more popular, here are my thoughts on the matter:
-Most 2D games are usually from East Asia, while the audience on this forum is usually western, meaning there is a cultural divide there. If you consider only western 2D games, you'll notice that they tend to be pretty popular too, but there aren't that many of them because making 2D games is harder. (I know there are eastern games that are very popular too, but those tend to be the rare ones that find ways to bridge that gap)
-The above point contributes to this idea that 2D games are longer and have less sex scenes, because eastern VNs tend to be more story focused, while western games tend to have more of a mix of story and sex to keep people engaged. (I know there's eastern games that are all PWP fap fests, but those are also in the minority compared to long drawn out VNs). 2D games are also much more likely to contain mosaics censorship, or bad translations, than 3D ones. (Though there are also some atrocioulsy bad engrish in some 3D VNs too)
-There is also the argument that 3D graphics are more realistic, and people tend to prefer them over 2D graphics. I think it depends really, as both can be really good, but if I had to guess, I'd say most people prefer 3D visuals over 2D, as long as they are done well. (There's plenty of uncanny valley shit out there. I'm talking about beautifully rendered games.)
-Due to the ease with which making 3D games is possible thanks to Daz3D and stuff like Honey Select, those types of games tend to get updates faster than 2D games, which require that artists put a lot of time into drawing different scenes. (Sure, setting up a good render can also take hours. But once you have the character model and have done a couple scenes with them, using the same model in different scenes does become a lot easier than having to redraw the character entirely for every new pose.)
