Probably that was jealousy as drugs pretty much zapped John of his creativity. Paul was doing the lion’s share during the Beatles’ final years. Paul probably just dabbled more than anything.
Don’t let me down
Across the universe
Both Lennon on the sparse Let it Be album and the only listenable tunes there.
I Want You (She’s So Heavy)
Come together
Because
Sun King
Mean Mr. Mustard
Polythene Pam
All Lennon from the otherwise saccharin pop of Abbey Road.
Lennon lifted McCartney from obscurity to stardom. McCartney would have been the most sought after studio musician in England otherwise.