I read alot. Saw many rumors. I'm aware of the various 'insider scoops'. I still maintain we really don't know what happened, more or less.
I'm certain of this though... when Greg Brockman walked out the door, they lost a major piece of talent.
That guy was a true believer. His enthusiasm was infectious. It traveled across the video link... You could feel how passionate he was about the future of artificial intelligence and it's capacity to change humanity for the better.
I'm sure he'll throw himself at something very cool for the next run.