I don't follow OpenAI or SV news all that much. Is this guy really that critical to the company? I thought Ilya Sutskever was the genius? Is this a non-compete thing, where they're scared Altman will take company secrets to a competitor, or is this dude actually a major factor in the company's success (and not just a lucky bystander)?
He is one of the most well connected people in tech and probably responsible for all of their partnerships and fundraising success. His departure in this fashion would make it really hard for them to raise as much money as they will need and potentially put them on a blacklist of a lot of YC companies. To top it off he'd probably raise a few billion and poach half of the team.
To the first point, they’re hugely well known at this point and could probably continue to raise money fine without him. But to your 2nd point, they wouldn’t be doing that in a vacuum. They’d be competing against him, and he could probably still out-raise them to do the poaching.