He probably considered himself an equal to the Beatles in that era, figuring his approach was necessarily better than anything they had to work with up to that point.
And yes, he proved himself to be human trash plenty during his admittedly illustrious career. I read so many stories of what seemed to be provocative mental illness coupled with genuine talent. Humanity sometimes bothers me to no end!
Enigma, thy name is John Lennon, and we accept his imperfections when balanced against his ample contributions to our history, musical or otherwise. The business mind of JL is often overlooked, though he had that genuine skill from the start - maybe he was just grateful Phil Spector salvaged Let It Be when it looked like it might never get released following the impending breakup.
Abbey Road and Sgt Pepper are, in my opinion, the top of The Beatles' creative game, with Revolver and Help! clearly showing the promise of where they were headed. Contrary to most public opinion I find the White Album to be boring,, indulgent, and overall disconnected from all their previous work. Let It Be was a step in the right direction, but had Abbey Road been their final release (as the recording sequence would imply), I bet Let It Be wouldn't have received the attention and accolades it continues to receive to this day.