That's been well documented, at least anecdotally (but reliably, I think), but what I wonder is when that type "behavior" became his M.O. Was it before or after his European sojourn with his band, which by all accounts was an ill-fated, mind-numbing, gut-wrenching, soul-crushing, wallet-emptying labor of love for all concerned. If he was already doing this before that, then, hey, not a lot of "sympathy" here, but if it was afterwards, then I can at least chalk it up to Music Industry Cynicism Brought About By Hyper-Reality Overdose.
In fairness, though, the guy does have skills of his own, and they are not insignificant. Which makes his..ahem..."reliance" on others something that I myself see no need to cover up. You produced a session, you conducted a session, if you didn't do all the writing yourself, what's the big deal?
But apparently it was... Ego's a bitch, I suppose.