Before Blade Runner almost anything could be science fiction. After Blade Runner science fiction meant detective noir with #tech_upgrade - clones, memory implants, dystopia. Or it was US truckers and/or the military fighting nasty aliens in spaaaaaaace. (Star Wars and its magic space knights was always more fantasy with a science fiction stage set.)
Blade Runner did it far better than the others, but then we had decades of mostly mediocre book knock-offs, especially in the UK. (Gibson gets a pass for taking the new trope even further by being a brilliant stylist, mixing in some tech orientalism, and inventing cyberspace.)
It's a stunning, iconic masterpiece of a movie with an unfortunate chilling cultural effect.
And ironically the Philip K Dick original was... very different.