I think you’re right. I reached that conclusion on reading the the Tower series. Easy to read, but are far too long as are most of his books. Imo he’s a competent writer, not a great one. To be fair I have never found him pretentious.
Some of his individual stories aren’t bad. Some lack originality and imagination imo.
Wouldn’t mind having his money. Wouldn’t want his mind though, I bet it’s really creepy in there.