To be honest, I think that when it comes to VNs being mainstream, mobile otome games have the better chance of pushing them to the mainstream than traditional PC or console games. For one thing, they're everywhere and their advertising is very on point. A lot are free, some are pay-per-route and it targets its intended audience very efficiently with pretty art, pretty boys, and romance. It's also often the entry point for a lot of players to the better VNs out there. Personally, I got into VNs with mobile otome, and a lot of people in the otome community can say the same. Also, otome players don't necessarily read just otome forever. Some of them, like me, also get drawn into more plot-based VNs like Fata Morgana, When They Cry, or liar-soft's steampunk games.
Also, there are a lot of indie otome/bl/moege devs who are doing good work and I've noticed that the number of them are growing and getting better. Like, some devs I've followed for years and you can really see their growth when it comes to art style and writing quality.