AVNs always have atrocious wishlist numbers. All of them.
Not all of them, not always. Law School has reached the 10000 wishlists for its release on Steam:
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Sure, very different games and all that jazz but getting good numbers is a possibility. The thing here is that Maya has been promoting the game non-stop for months on social media, he's incredibly active in his server and in others, he's always interacting with the community, ... And obviously the game being very good really helps too.
Obviously, doing those same things does not necessarily guarantee success, but it's necessary if you want to market your game. There's a reason why massive brands known by pretty much everyone like Coca Cola or McDonald's still keep advertising all the time, you need to stay in people's minds.
Also, I believe AVNs live or die by how appealing the girls in the game are, and as an outsider who hasn't played Game of Hearts based on what I can see, Meredith seems by far the main girl of this game, but the reality is that she's not going to be visually appealing to that many AVN players. She may be a great character but the average AVN player isn't going to be attracted to her looks. If they were attracted to her, AVNs wouldn't be filled with supermodels XD