They might have refused to do the same song twice late in their career. But they built their empire on cranked out clone love songs:
Love Me Do
Please Please Me
I Want to Hold Your Hand
Can't Buy Me Love
Eight Days a Week
...
Heck Paul just about admitted it in "Silly Love Songs" when he had Wings. And that's the part of the Beatles catalog that keeps me from every being able to rate them higher than a C-. These are the guys that INVENTED formula pop, just because they eventually moved on doesn't forgive them their sins. You want to know why all Nickelback songs sound the same? Because the Beatles proved that making the same song over and over was a license to print money.
You're not suggesting these particular songs are clones of each other, are you?
You may have a point concerning the very early Beatles work, but they were doing covers then as well as original songs.
As for "moving" on, not many of today's rock bands will have the cojones to do that.
Don't misunderstand, I think there are fresh sounds being written today, but then the band or artist generally re-writes that fresh sound over and over until it's stale.
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.