I think when you look at science fiction films before Star Wars, it's drawing on a very limited pool of influences and indeed, not a whole lot going on. In the 60s, there was a brief trend towards comparatively "hard" science fiction due to the space race, but it didn't last. A lot of the genre, at least in film and at least in the US, was still stuck in early 20th century pulp science fiction, red-scare alien invasion scenarios and tedious propaganda films meant to interest the general public in space.
I think one secret to Star Wars success is that it took a whole bunch of genre influences, in particular influences which were becoming increasingly stale themselves, and created a new context with them. The Western genre pretty much died out in the 70s, largely because the historical consciousness of the American West was changing, but by putting western elements in space a lot of those problematic elements were removed. Similarly, world war 2 movies. It's also kind of a martial arts film at a time when martial arts were becoming a big thing in the US, but without the implied foreignness of real martial arts. Star Wars is an incredibly escapist franchise. By taking elements from the real world and putting them in a science fiction context you can strip these things of a lot of their inherent politics (although I would argue you can't, the politics of star wars are very obvious, but a fan enjoying the films might not see that).
Star Wars was also one of the first franchises (besides Star Trek) to really weaponize the concept of fandom and what we would now call "geek culture". Roger Ebert made the comment (albeit in regard to the prequels) that if a person is willing to camp on the sidewalk for 2 weeks to see a Star Wars film, they're probably doing that less out of love of the films and more out of love of being the person who camped on the sidewalk for two weeks to see a Star Wars film. Star Wars convinced a lot of bored and disenfranchised people to stake their identity on it, and that's a powerful force because those people then become advocates for the film, essentially unpaid PR representatives, and marketing a film is extremely easy in that environment.
Personally, I'm incredibly bored of Star Wars and its aesthetic. I think it's become the default aesthetic of science fiction, and nowadays it's exciting to me when a science fiction film or series doesn't look like Star Wars.