"What if I don't like Rolls Royces?"
"When the revolution comes you'll have no choice."
Yeah, everything's going to be just peachy when we're all living in tiny houses, eating fake meat and voting through our cellphones.
Of course most of these billionaires have paper assets. Look at Bezos or Gates or Buffet or Page - their wealth is on paper.
This is in contrast to say the Sultan of Brunei or the King of Saudia