Until Star Wars, science fiction was the exclusive province of the five or six most intelligent kids at any school. Star Wars introduced science fiction for stupid people, thereby doing humanity a great disservice.
To be fair, people like Chris Trevas did try to make Star Wars a bit more like old-school science fiction to fix that.
I heard Lucas tried to use the Science Fiction field to push social agendas due to his taking anthropology in college.
Besides, Star Trek also was a bit guilty of that as well.