This is tough because the Beatles have pretty much influenced the entire genre of pop & rock music (and some others), so if they had never existed, who knows what the music of the past 50 years would have turned out like.
I'd probably be listening to more blues, bebop, and swing.
Beach Boys, S&G, Clapton (and his associated groups), Elton (as long as he had Bernie), Santana, and of course , The Who, to pick a few of the best (imo) pop/rock artists that I'm certain would have attained their legendary status without the Beatles influence. They have talent approaching that ...