gator,
You got any idea what caused the rift between Collins and Gabriel?
There was no rift. In fact Collins and Gabriel worked together several times after. Phil drummed on Gabriel’s third album (’Intruder’, ‘No Self Control’, ‘Biko’), and Pete sang backing vocals on Phil’s “Take Me Home.”
Pete just felt it was time to move on, and in retrospect, it was the right time to do it. They never were going to top “The Lamb” with Gabriel, and it freed Genesis to go in another direction that led to even more success for them.