I think horror recently has delved into more serious themes because it’s en vogue but yeah, there’s always been good horror movies that led the pack. But I think they were fewer and farther between in the past. Same can be said for a number of genres though, including science fiction, and action/adventure films, even comedy.
A24’s primarily, or at least its most high profile movies, have been elevated horror but that’s not exclusive. I do think there’s a halo effect around all of their films right now. In general, I find their movies to be pretty high quality - Hereditary, Midsommar, The Witch, The X trilogy…all solid movies IMO.