If the cfo feels the company will be worth hundreds of billions one day, he does not retire usually.
Becoming cfo is probably more than he ever dreamed off, why give it up.
Anyhow i am not required to understand it, maybe he does not either.
This is true. Also even if he retires at 50 or whatever, I never understood why his investment in Tesla was so small. He generally instantly exercised and sold all his options. There are probably people here on this forum who own more shares of Tesla than the CFO?