This was something I started wondering about when I was reading a thread about Star Citizen, and about how space combat flight games were much less-common than they had been at one point, how fans of the genre were hungry for new entrants.
Looking at this list:
https://en.wikipedia.org/wiki/List_of_space_flight_simulation_games#Space_combat_games
…there really were far more games in the genre being released in the late 1990s and early 2000s than there have been recently.
A similar sort of phenomenon occurred for World War II first-person shooters.
https://en.wikipedia.org/wiki/List_of_World_War_II_video_games
Back around the same time period, there was a glut of games in the genre, and they really have fallen off quite a bit.
Whether it’s a genre like these two, that hasn’t seen many new entrants recently, or a genre that just never grew as much as you’d like, what genre would you like to see more of?
https://www.thegamer.com/games-like-castlevania/
Looking at this list, maybe – depending on the era you like – Bloodstained: Curse Of The Moon, or Hollow Knight for Metroidvanias with similar-to-Castlevania themes?
I have only briefly played Salt & Sanctuary, but it looks thematically kind of like Castlevania, and it’s a popular Metroidvania.
EDIT: It looks like the Bloodstained series is trying to fill in the classic Castlevania gap. I kind of preferred the later Castlevania games – PS2 or GBA – but this might be what you want. The Steam reviews have people grouching about how Konami isn’t doing this any more:
or
https://store.steampowered.com/app/838310/Bloodstained_Curse_of_the_Moon/
https://store.steampowered.com/app/1257360/Bloodstained_Curse_of_the_Moon_2/