well like a year and a half ago it started dawning on people that ai could be more reliably used with reasonable consistency and it conviced a lot of people to give it a go. a lot of games got made and i guess they are in the mayority all nts/ntr tinged because the devs saw the success of the early games in the genre (Blurring the Walls, My New Girlfriend, Moonripple Lake).
being in a niche also initially really helps a game's visibility i think, so that probably helps devs decide to go for netorase and netorare.