I find the close partnership with Microsoft and their vision of "Creating safe AI that benefits all of humanity" difficult to reconcile. Open source vs commercialism could definitely be a reason for the split.
How so? Think about it, Microsoft is very risk averse. Hell, even to get the Xbox project going they had to fight so damn hard because "we're not a games company, we make Windows and Office"
It's completely illogical to say that just because an AI company isn't open source it can't strive to also be "safe".