Say whatever you want about where he took the franchise later and rereleases and whoring it out for every red cent... The man had a hell of a vision back in the day
All he did was read Joseph Campbell's "The Hero with a Thousand Faces" and turn it into a sci-fi flick. Don't get me wrong the original three were good pictures, but it is the most formulaic way to make a story. You can find every step in the hero's journey like clockwork.