Billionaires do pay their fare share.
$1,000,000,000 divided by the average in-state annual tuition cost $10,661 divide by 4 years equals tuition for a total of 23,447 students. That excludes any government administrative costs, which would significantly reduce the number.
Then what?
Most billionaire wealth is not CASH! it is equity in companies and real estate. Selling that equity is the only way to raise cash to pay tuition expense. Who will purchase that equity? Selling it off all at once reduces the sales price (supply -demand) so full value is not realized.
Another plan that is not thought out!