The Beach Boys become the poster child for pushing the envelope in the studio, I presume?
The thing is, even if you remove the Beatles' song catalog from the world and made John, Paul, George, and Ringo a bunch of relative unknowns, there's still a lot of changes to the musical world they did.
They weren't the first singer-songwriters, but they made the idea of putting songwriting on par with performing songs. Popular music before rock and roll was about how each artist interpreted a set of songs from a "standards" songbook. After rock burst on the scene, and especially with the Beatles' popularity, it soon became the norm for musicians to focus on self-written pieces and gave rock a DIY aesthetic that made it stand out compared to other genres.
And then starting with Rubber Soul those lads from Liverpool started to push the boundaries of what could be done with studio equipment. Previously studio sessions were just to record an artist's repertoire and create a substitute for people who couldn't go to live events; live albums were considered more important for quite a while. Then the Beatles came in and made the studio album the currency of rock music, taken to its logical conclusion by subgenres like progressive rock which eschewed the 45 rpm single and released albums that had one song per side. And in trying to keep up with their studio experimentation, the engineers at Abbey Road Studios came up with increasingly novel ways to record music. Automatic Double Tracking was created because John Lennon couldn't be arsed to sing twice into a mic to make his voice stand out. The practice of using DI on bass guitars came about in part because Paul McCartney didn't like how his bass was drowned out on the recordings.
So without the Beatles, there's a lot that would change musically. Perhaps another band takes up the slack in becoming pop culture titans, while yet another act revolutionizes the recording studio.