However if i was in his shoes, why would I take a desk job when I can be flying jet plains and going to space....
Well, his space missions to date have been more than joyrides. He and his crews have performed both orbital science and community outreach to the young. Being at NASA amplifies his ability to see both done. Plus he gets to *try* to deal with some of the agency's suboptimal projects to free up budget for more deserving efforts.
Indications are the gentleman cares about doing more with his life than just having a good time. After all he could use his time and money to buy a superyacht and a pro sports team and live the life of the rich and famous. Instead, he has been taking on more significant challenges. And make no mistake, the NASA admin job today is a big challenge (especially the political side).
There is an ethos common among the tech community that is sadly rare among politicians, celebrities, and elites that Mr Isaacman likely adheres to: "Try to leave the world a better place than you found it."
From the outside it looks like he's well on his way just by his space missions.
Now he gets to play on a bigger and harder stage.