You can’t build “working with amazing people”. At least not in a short amount of time. I bet that this was a significant part of the decision for Andrej.

The overhead of maintaining and running things isn't interesting to most creative folk. They'd rather others deal with the minutiae (managing a company, etc) so they can focus on their thing.

i can play by myself, or i can join some friends, and make the play more joyful

No, money is not the only barrier to building things. I think karoathy could build his own lab if he wanted, but it would be years of doing things he doesn’t want. Why waste time running a business when he’d rather be researching?

Do you have any idea how much it costs to build a frontier model and how much money it takes to enable R&D at the cutting edge?