The Blair Witch Project was by no means the first found footage horror film, but it was the first one made with any real skill, and it was the film that popularized the format and essentially set the standard for it. Earlier found footage efforts like Guinea Pig: Devil's Experiment and UFO Abduction are not exactly horror classics.
Yes, Fatal Attraction paved the way for a bunch of terrible exploitation movies. Obsession probably will too. That doesn't make it a worthwhile classic by any means, unless you consider shit like Blood Feast and Ilsa, She Wolf of the SS to be classics as well. And no, Fatal Instinct absolutely did not invent the erotic thriller. Are you serious?
People remember The Exorcist because it was a brilliantly written, acted, and directed horror masterpiece with a lasting cultural impact. People remember The Evil Dead because it basically just got lucky and made a lot of money as a cheap and silly grindhouse B-movie.
Let's use another example: Everything Everywhere All At Once. That movie came out only four years ago and has already aged horribly, despite receiving massive amounts of hype and even a Best Picture Oscar win. Very few people today are even willing to admit that they ever liked that movie. Stephanie Hsu certainly did not become a massive Hollywood star because of it.
Truthfully, there are no massive Hollywood stars nowadays, other than the ones who have been around for decades. Hollywood culture has changed drastically since the era of streaming took off, and nobody watches movies because of movie stars anymore.
Will Inde Navarrette and Sydney Sweeney continue to have roles in movies and TV shows for years to come? Most likely. But that's not the same thing as being massive Hollywood icons who will remembered decades from now.