He was the one who partnered with Microsoft and turned it from a non-profit to a for-profit company.
In the world where Sam Altman leads OpenAI to market dominance and eventual acquisition by Microsoft for $400B or whatever, he obviously would represent an important part of what Microsoft would be buying and would be compensated accordingly.
It is the reason why CEOs (not Sam, apparently) are usually compensated in stock options. Golden parachutes are some sort of severance when the CEO gets fired immediately from the new company, eg. Twitter.
He's totally the guy who made OpenAI into ClosedAI, but money was clearly not his motivation.
A similar (but even more complicated) case is currently going on over at Sculptor Capital Management, where former management is suing current management because they have chosen to go with a "worse" acquisition deal that would let current management stay on-board. This is despite shareholder approval to the "worse" deal. https://www.pionline.com/hedge-funds/ex-sculptor-executives-...
In fact, to prevent this situation is exactly why golden parachutes exist.
It's also totally unproportional compared to what Sam would've gotten if he owned equity.