Dr Robert, thank you for your post very much. You have expressed here very true ideas IMO.
I think the band started to disband because of the inner coup staged by Paul. The band was founded by Lennon, he was its leader. But somebody started to oust the founding member. Things are not done that way, if you want to be a new leader form a new band. I should say that Lennon was extremely democratic, he never claimed leadership. And it was ok while nobody else claimed it either. Kind of all equal, at least, John and Paul equal. But when Paul with his ambitions tried to get the upper hand it all collapsed. The other guys were not such nincompoops, he thought they were, to tolerate this.
Nevertheless, I love Paul and right now I am into his Speed Of the Sound.