So we finally get the other side of the story on why Jimmy [left] the Pumpkins, again in 2009...
In the newest issue of Rolling Stone (preview here), Billy, takes a little pop at former drummer (as well as the rest of the original SP line-up) and musical soulmate Jimmy Chamberlin,
“Jimmy is a destructive human being, and people who are destructive break things,” Corgan says. “I don’t see me reaching the highest levels of my creativity if I’m unhealthy and if I have unhealthy people around me.[...]” After Corgan told Chamberlin he was out...I was like, ‘Fuck you,’”, Corgan recalls. “‘Go ride around in a white van for the rest of your life.”
Chamberlin becomes apoplectic when he hears Corgan’s account. “In the middle of the last tour, Billy said it was the agent’s fault, then it was the band’s fault, then it was the fans’ fault,” the drummer says. “Yes, in the past, I was a destructive human being. I was a complete drug addict and a complete loose cannon, but I’ve taken responsibility for my life.” "In the grand scheme of things" he adds... it's a few Gold records and a bunch of money... I have a wife and kids and I am completely happy"
Jimmy's sentiments have been borne out in his recent clinic appearances (here and here) and in his statement when he left; where he wishes Billy all the best, and contrary to Corgan of his Jimmy's ideas, quite happily accepts Corgan's definition and pursuit of 'happiness/success'.
Updated 28 November 2011: Corgan makes an indirect apology for these comments; they were 'just the ugliness that goes with breaking up'