On that note, I find it interesting how pre-military and post-military Elvis are almost different artists. Pre-military Elvis was the Face of Rock and Roll, helping to bridge the genre's roots in African-American rhythm and blues with White America. Post-military Elvis was closer to a pop musician, in part because rock music had moved on without him.
The Beatles' key innovation was in moving rock music from "Rock and Roll" to "Rock", turning what was a budding genre into the form of pop music that dominated musical discourse for decades (arguably ending its run at the top only in the 1990s or even 2000s). The Fab Four helped pioneer the studio album as the currency of music releases (even as they released singles that would inevitably reach #1), helped integrate other genres like Indian music or avant-garde electronica into the mix (even as they still stuck to the guitars/bass/drums core), and created the singer-songwriter as the Platonic ideal of musical expression over the "standards song book" approach (rendering Tin Pan Alley and its ilk increasingly obsolete).
The Beatles' key innovation was in moving rock music from "Rock and Roll" to "Rock", turning what was a budding genre into the form of pop music that dominated musical discourse for decades (arguably ending its run at the top only in the 1990s or even 2000s). The Fab Four helped pioneer the studio album as the currency of music releases (even as they released singles that would inevitably reach #1), helped integrate other genres like Indian music or avant-garde electronica into the mix (even as they still stuck to the guitars/bass/drums core), and created the singer-songwriter as the Platonic ideal of musical expression over the "standards song book" approach (rendering Tin Pan Alley and its ilk increasingly obsolete).