My guess is that OpenAI has been taken over by three letter agencies (the adults have arrived) and the people leaving now are the ones who have a conscience and refuse to build the most powerful tool for tyranny and hand it to one of the most evil governments on earth.

Sam, being the soulless grifter and scammer he is, of course will remain until the bitter end, drunk with the glimpse of power he surely got while forging backroom deals with the big boys.