Ah, I gotta disagree. While it did make things follow it's footsteps with Space Opera-often-with-fantasy-elements, the crop of movies before it, which included a lot of too-serious affairs trying to be 2001 (poorly), and plenty with no more realism than SW too.... there aren't a lot of movies in that timeframe I'd consider good. SF movies needed some new aim, some new hook, and it got a lot of fresh blood into SF, which meant *more* SF, of all types.
Here is the SF films of the 70s. Planet of the Apes was the biggest franchise. Take a look how few there were in '76, the year before SW. There's Logan's Run and that's about it. Check '79, two years after SW. You've got Alien, Black Hole, Star Trek, Buck Rogers, and just a lot more SF movies period.
Terminator 2 - Judgment Day
Star Wars - Episode V - The Empire Strikes Back
Jurassic Park (1993)
The Thing (1982)
The Fifth Element
Starship Troopers (1997)
Captain America II - The Winter Soldier
There are additional Sci-Fi movies which are rated very high and liked by many.
You aren't exactly countering the whole watering down idea in your first paragraph, if anything it sounds like you aknowledge it happened but argue that it didn't kill the genre. That's like saying the Beatles didn't kill music, it goes without saying.
But I agree that there is some complexity in how Sci-fi movies actually built their audience and that the evolution is Worth discussing. It'd argue television was a format of more influence in the genre during the last century (maybe the tipping point was just after the 80s, it could be argued).
back to the future trigoly
India johns trigoly
pirates of Caribbean trigoly
the amazing spider-man 1 and 2
the wolverine movies
last two x-men first class and days of future past
batman trigoly with Christian bale
ghost busters movies
hell boy 1 and 2
The unlimited Avenger the movie
The unlimited Avenger 2 rise of black panther animated cartoon
doctor stranger animated movie
captain American first The Avenger
captain American winter solider
thor the movie
thor dark world
The Incredible Hulk with ed notion
the hulk with ang lee