I can’t deny that Epstein was crucial to the Beatles’ rise; but once they had achieved stardom he made a series of bad business decisions (such as the Seltaeb merchandising deal, which lost the Beatles vast sums of money), and as time went on he became increasingly irrelevant to the band’s affairs (which some speculate contributed to his despondency and suicide). George Martin, OTOH, always had an important role to play, and as a contributor the music itself (which, tellingly, showed a tendency to suffer when he was absent).
Probably Epstein’s main flaw as a negotiator was that he seems to have been more concerned with chalking up a deal at all than with how good a deal it was. In the early years this was an asset as you say.
By agreeing overly eagerly to things like the Seltaeb business he probably thought he was maintaining control over the enterprise, because by having an exclusive deal in place he’d have better legal standing against infringers. But by the very nature of a merchandising deal is relinquishing a piece of control to the other party.
No question there. There’s some interesting stuff in the Anthology book, for example Paul saying that Pete hooked up with a stripper girlfriend in Hamburg, spent most nights with her, or what was left of the night after they were done working, and would still want to sleep in next day when it was time to go back to work. In the mountain of things said by the remaining Beatles, and others, about Pete, among the tide of lambasting and slamming, every so often you come across a comment that suggests he wasn’t as awful a drummer as has been made out. Regarding George Martin’s evaluation of Pete, somewhere I’ve read where Paul was quoted as being initially reluctant to fire him, saying he was “working out great in the clubs”. At this time Ringo, while a better drummer overall and certainly more creative, couldn’t keep the beat that steadily (again according to Sir Paul), and Martin initially thought Ringo was another dud. Even then, drummers got no respect anyway. I think more than his drumming ability it was just that Ringo is a far more engaging and fun person to be with, judging from what I’ve seen of him in documentaries and other TV material. The man could be a comedian, while Pete was kind of a dud in that regard too.