Yeah, he made his first big money from PayPal (I think around $300M), and then invested most of that money in SpaceX and Tesla, and that's how he became a billionaire.
180m after taxes -> 100m to spacex / 70m to tesla / 10m to solarcity.
remember before the gvt pumped money into his companies they were on the brink of bankruptcy. once they got the nasa contract spacex immediately got profitable. which allowed musk to use spacex money to loan to tesla. n also use the govt loan to tesla to make the save the company.
gist of the story - the money is in gvt. same applies to thiel.
