Perhaps it's takes a certain breed of people, but I'm not sure what I would DO with $750m. Buy a super-yacht I guess? Invest the money and make 10x more of it? But then what?

We've seen the new space race, but that domain seems crowded at the moment.

Use the money to cure cancer or other global health problems? Wealthy people don't tend to spend their money like that (Bill Gates being an exception). Why is this?

Buy influence and dictate politicians in backroom deals? Seems pretty cynical, but a possibility.