This stuff is utterly incomprehensible to me as well, but I don't think Haskell is trying to be a mainstream use-it-for-everything language. It does get plenty

This stuff is utterly incomprehensible to me as well, but I don't think Haskell is trying to be a mainstream use-it-for-everything language. It does get plenty of real-world usage and the people who like it really like it, so for a language so complicated to get as much use as it does sounds like it "took off" perfectly fine