The board was Altmans boss - this is pretty much their only job. Altman knew this and most likely ignored any questions or concerns of theirs thinking he is the unfireable superstar
Imagine if your boss fired you - and your response was - I’ll come back if you quit! Yeah, no. People might confuse status with those of actual ceo shareholders like zuck, bezos, or musk. But Altman is just another employee
The shareholders can fire the board, but that’s not what he’s asking for. And so far we haven’t heard anything about them getting fired. So mostly this just seems like an egomaniac employee who thinks he is the company (while appropriating the work of some really really smart data scientists)
Think you're missing the big picture here. Sam Altman isn't an "easily replaceable employee" especially given his fundraising skills.
One can imagine Microsoft, for example, swooping in and acquiring a larger share of the for-profit entity (and an actual seat on the board, dammit) for more billions, eliminating the need for any fundraising for the foreseeable future.
If a lot of top engieers follow sama out, now that's a real problem.