If your net worth is in the billions then extracting few millions for retirement is not a problem.
I just don’t understand how once you reach a certain level of wealth you are functionally locked out of ever accessing it except on paper. Someone must have kept their wealth or cashed out (one way or the other) at some point. It feels like, if true, no business would ever exist more than 30 years but clearly there are many businesses that have.
Typically at those levels of wealth there is a “family office” which is just a word for “hedge fund” that’s only clients are the family. Like any hedge fund they can use those shares as parts of lots deals to diversify, manage risk and pull out cash.
Sometimes it’s even simpler, dividends can provide a significant cash flow for large shareholders.
In any case, it would be extremely strange for someone to get very wealthy and then hold most of their portfolio in cash.