When Beatlemania reached the U.S. we had the Beach Boys, but not Jefferson Airplane or the Doors. I lived in Las Vegas when they hit and most of us guys didn't like them at first either, then we noticed all the girls loved them, saw Hard Days Night and wished we were one of them.
I think the biggest reason why the Beatles had such a huge impact was that in early 1964, there were very few American pop groups that were extremely popular (the Beach Boys being one of them). People forget what happened on that fateful day in 1959 when Buddy Holly, Ritchie Valens and J. P. Big Bopper Richardson were killed in that tragic airplane crash--it wasn't called The Day the Music Died for nothing. These three musicians--had they lived--would have become the second generation of major rock and roll successes.
Along with Elvis Presley being in the Army at that time and Chuck Berry's legal troubles in the same period, no wonder the first wave of rock and roll music was nearly gone by 1960. The Beatles and the subsequent British Invasion of 1964-1967 reinvigorated rock and roll, which set up the second generation of rock and roll music that alas was gone by the end of 1970 with the deaths of Jimi Hendrix, Janis Joplin and the fallout from the Rolling Stones' infamous concert at Altamont Raceway just east of Livermore, CA at the end of 1970.