Well, let's imagine I own say $3 billion in stock, which is not unheard of, but I'd call that mega wealthy. Let's say I need $20 million a year in cash to live. Anything spent over that is buying assets, like another Gulfstream. So, how many years can I borrow $20 million, pay the interest, and not run out? This presumes the $3 billion doesn't appreciate, which generally it does.
And maybe every so often I sell some stock and pay it all back and taxes too. Maybe every ten years I have an enormous tax bill. Or not.
A feller can live pretty well on $20 million a year. It's been done.