This. The Beatles happened upon the right things at the right time and therefore cemented their place in the zeitgeist as the progenitors of a lot of stuff that they themselves probably wouldn't even take credit for. Taking psychedelic rock as an example: "Pet Sounds" predates "Sergeant Pepper's" but only one of these albums gets the graphic t-shirt and VH1/NPR/Rolling Stone retrospective treatment. This happens all the time and is largely a product of critics coalescing on narratives simple enough for them and their audience to reason about. It's easier to say, for instance, that Black Sabbath invented heavy metal because their name sounds a lot spookier than "Sir Lord Baltimore" or "Blue Cheer", not because they actually did it.