> To be honest though, I don't really understand how normal money-you-buy-stuff-with works for people who are billionaires when most of their wealth is in stock

> To be honest though, I don't really understand how normal money-you-buy-stuff-with works for people who are billionaires when most of their wealth is in stock and options. He takes out loans with his shares as collateral to get spending money. Why not just sell? Because he expects the shares to appreciate more than what he'd pay in interest and/or to retain the shareholder vote.