Musk spent a lot of money trying to teach people that that doesn’t work.

He’s a billionaire because he owns the majority of Tesla and Tesla is very valuable. He has no taxable income unless he draws a salary or liquidates some of his Tesla shares

He demonstrated it by liquidating some shares and getting a tax bill

Billionaire spending money comes from a deal with a bank - the billionaire gets as much credit as they like, the bank is paid back by their estate upon death