>>713370594 (OP)They're harder to make than most other genres and harder to monetize, simple as.
Like there's a reason most action games copy Soulsborne combat nowadays, and it's not because Dark Souls has some super-deep combat system. It's because it's really simple; most weapons only need a 2-swing combo and like 90% of the groundwork has already been laid out.
Whereas if you wanted to make a proper DMC rival, you'd need unique animations for all the weapons, unique movement mechanics, probably special gameplay mechanics/gimmicks, etc. This isn't even getting into bosses and enemies to take advantage of all that. There were a number of DMC clones on PS2, but games like NG and Bayo show you don't need a unified control scheme.