The Beatles invented formula pop ?
Are you familiar with what preceeded them ? Manufactured pretty boy pop like Fabian, Frankie Avalon, and Bobby Rydell that made Menudo or New Kids on the Block look profound. Remember Lesley Gore and Neil Sedaka ? Remember the affected pseudo-profundity of Neil Diamond ?
EVERYTHING between Chuck Berry and the Beatles was formula pop.
True formula pop had been around. But the Beatles hit the formula that's still used today, in the world of pop music the Beatles were the screeching emergency brakes on progress and change.
What about the Fabulous Wailers and the Sonics?
The Kinks revised their sound after touring with the Sonics.