IT was such a huge hit, Chapter 2 made 67% of what Chapter 1 did, where Conjuring 2 actually made more than the first film. And for the talk about how iconic Pennywise, most people had no idea he was actually an alien.
The reason why I rate Conjuring, Scream, and Hellraiser “over” IT is shear volume and continued relevance. New movies for each of those franchises are in the pipe. Each of those franchise have more films, and therefore more methods of “entry.” The IT reboot hit a perfect spot that capitalized on Stranger Things and the renewed interest in the 80s. That interest is starting to wane, and because it’s an homage rather than a genuine article of the time, there’s less appeal in revisiting it.
The further we move away from it, the less of a draw it will be. In three years, it’ll be a tier 3 film.