You can have the best leaves and branches but without good roots & trunk, it's pointless.
From everything I can tell, Altman is essentially an uber-leader. He is great at consolidating & acting on internal information, he's great at externalizing information & bringing in resources, he's great at rallying & exciting his collegues towards a mission. If a leader can have one of those, they are a good leader but to have all of them in one makes them world class.
That's also discounting his reputation and connections as well. Altman is a very valuable person to have on staff if only as a figurehead to parade around and use for introductions. It's like if you had Linus Torvalds, Guido van Rossum, or any other tech superstar on staff. They are valuable as contributors but additionally valuable as people magnets.
It would and should give ppl pause. I suspect Sam is just inside Microsoft for the bluff. He couldn't operate in the way he wants -- "trust me, I have humanity's best interests at heart" -- while so close to them, I don't think