Now, I like the Beatles as much as the next man, but it seems to me that musically they didn’t have as huge an influence on what followed them as their towering reputation might suggest. When you think of the classic sound of the later sixties and seventies - it’s more akin to the blues-rock pioneered by acts like the Yardbirds, Cream, Led Zeppelin, a style already emerging in the early sixties and not closely related to the purer pop the Beatles were making at that time.
Not many acts of the late sixties or after really sound like the Beatles - ELO, maybe people like Roy Wood, much later Oasis and some other Britpop bands. And you can probably hear a McCartney influence in singer-songwriters like Billy Joel and Gilbert O’Sullivan.
The Beatles’ huge success did make it acceptable, de rigeur even, for artists to write their own material, so they deserve credit for that. But their musical style seems to have been a bit of a cul-de-sac. Maybe nobody dared copy them too blatantly?