Running out of billionaire's money would be a good thing[1].
If they don't have money then they can't buy elections and aren't insulated from the consequences of their actions.
[1] Note: I don't really think we should literally take all their money. Just enough to reduce some of the power imbalance.
All their "money" is in business ownership percentages. It's not money.
It's ok if they pay their taxes in shares, in case they ran out of money.
That's even better. You just transfer beneficial ownership and route dividends to a different bank account. And now you have a LOT more Americans literally invested in Amazon/X/Meta's success. But poor Jeff, he did have to sell his yacht (no, the other one).