You want to know why it’s so hard to adapt H.P. Lovecraft stories to film?
It’s simple: the concepts of Lovecraft’s stories are too big for most people to see and believe.
If you read a story like “The Call of Cthulu” and create in your own mind a vision of R’lyeh (where dead Cthulu waits dreaming), that vision is likely to be far more terrifying than anything that Hollywood could give form to. Buildings and hallways with impossible angles in a slime-covered city risen from the bottom of the ocean tend to be hard to bring to life on a budget, even with CGI.
There is one film, however, that did Lovecraft right. If not literally, then certainly in keeping with the spirit of the material.
It’s a film that deserves your attention, and a space in your collection.