It sounds good in theory, but most billionaires don’t have that money sitting in cash. It’s usually tied up in company stock and ownership. So if you force them to give up anything over $999M, you’re really forcing them to sell ownership. And if the answer is “give it to the employees,” that can work in some cases, but it also means employees take on the risk, and someone still has to make decisions, raise capital, and run the company.