That's true. Normally these types of games are just a protagonist with an harem, with his girlfriend as another NPC. But someone like Eva Kiss I think could create an interesting route. Maybe start with threesomes, voyeurs and partner exchanges and end with a cuckqueen routeThey're not popular because they're not even nearly as well-written as the other paths.
I like it better when the protagonist is a chad than a cuck. I'm not saying that my ideal route is better than the current ones, it just frustrates how difficult it is to find games to be a chad, and yet have a thousand options to be a cuck.