Star Wars was borrowing heavily from Seven Samurai not just western films. Thus swords vs blasters works the same way swords vs arrows do in those films etc.
There are basically infinite ways to remix old stories like that. Hell even just the editing significantly improved Star Wars over the original script.
Yeah point is it was heavily derivative, as are most of the films during the last golden age of film (1970s-pick when?), but the technological advances were dramatic enough and audiences didn't have home entertainment systems and access to every film ever so these films were incredibly novel culturally speaking.
I think two things are going on, everyone remembers movies they watched as a kid/teen and thinks they where unusually good. It’s not that there was a golden age of movies, it’s that you personally had seen fewer movies.
That said, the ratio of original movies to sequels/franchises changed. Fast forward 20 years from Star Wars to 1997 and sure yet another Titanic, Jurassic Park 2, and a James Bond film but also, Men in Black, The Fifth Element, Liar Liar, As Good as It Gets etc so still mostly original movies.
But fast forward to 2017 and the top 10 movies included: Pirates of the Caribbean 3, Harry Potter 5, Spider-Man 3, Shrek 3, National Treasure 2, The Simpsons Movie, and Transformers. I Am Legend based on a book and 300 based on a comic. So only Ratatouille was actually new.
There are basically infinite ways to remix old stories like that. Hell even just the editing significantly improved Star Wars over the original script.