Additional sauce here.

Mr. Altman’s departure follows a deliberative review process by the board, which concluded that he was not consistently candid in his communications with the board, hindering its ability to exercise its responsibilities. The board no longer has confidence in his ability to continue leading OpenAI.

Good riddance. ChatGPT went from great to garbage fast.

I would hazard a Guess he either pissed off Bill Gates and or some Corporate Suit at Microsoft.

Microsoft is a major investor in Openai.

Was he replaced by AI?

Umpteenth lesson for entrepreneurs don't sell you work to those that control Wall Street and the corporate boards unless you plan to exit. If you don't agree with their agenda you are going to exit, but not by your choice nor on your time table.

Board member and President also quit after this announcement. This smells like a palace coup. No one fires the CEO of a rising star company… unless he objects to the NSA taking over his AI research summation bot for use against Citizens.