'Popular' - well, of course. Glittering generality though, re whatever 'pop-music' might signify. But a step-change in originality, craftsmanship.. actual 'orchestra'-tion ie using Real Instruments! and not synthesized-pap. Then there were the movies and esp. Yellow Submarine etc. They grew from pranksters into a phenomenon that defies some trite slogan. Hey.. they even understood dynamic range .. imagine That!
The '60s - '70s were intertwined with Beatles; cross-pollination reflected, reinforced the social try-at revolution VS the stodgy establishment, whichever side of the pond. (Add Dylan for leavening; never mind the non-singing mumbling - call that, pre-rap rap.)
BB - there was execrable formulaic trivia; AB - there began to appear actual Thought, even in the $pop 'genre' - along with the formulaic bopper-trivia, natch. IMO.
Overrated -?- compared with What?
JS Bach - guilty. The Beach Boys.. Elvis.. ?
Peter, I wonder at your experience of the US pop vast-wasteland pre-Beatles.
How 'Rated' need you be - to change everything that followed?
ie I demur.