“Billionaire” is a convenient modern buzzword. It used to be “millionaire”. The classic joke from Austin Powers where Dr. Evil demands money is a good example. It’s just inflation.

Plus, a lot of “billionaires” are only considers such because they own shares in their corporations. It’s a “theoretically if they could find a way to sell all of those shares at the current price without tanking the market value of those shares in the process, they could get $X billion from that”.

If there were a theoretical global revolution, on of the the first steps of eating the rich is to seize and nationalize those businesses. Later, land reform will seize the extra mansions they own. They will still be left with adequate personal property to live quite comfortably. Finally, the justice system will need to evaluate what labor laws (or other laws) they may have been violating for years and using their wealth to get away with.

Start with the biggest fish and watch as the rest start to downsize voluntarily and cut deals to avoid jail.

I don’t expect to see any of this in my lifetime. Not in any major country, and certainly not globally.