The Bernie Sanderses and Elizabeth Warrens of the world have seized on these numbers as an indication that capitalism directs wealth and income to the rich and privileged.
What a bunch of hypocrites. We've long been lobbying (since the early 1990s) for allowing young Americans to put their 12% FICA tax into a personal account that would hold an index fund of all stocks. If we had done that, then nearly all 50, 60 and 70 year olds would have substantial wealth in personal accounts. Even the poorest Americans would own stock.
The liberals (most of whom have substantial stock holdings themselves) screamed about the stock market being "too risky" - but of course equities are only risky in the short term. But NOT in the long run, as 150 years of stock market performance reveals.
So now, only higher income Americans own stock and Liberals complain about it endlessly. They apparently don't want America to be a nation of owners. That's the best way to spread the wealth.