Mythology
He said that with the current distribution of wealth in the US, wherein the top 0.1% control 90 percent of the wealth, isn't sustainable.
I have heard similar numbers for most of my adult life. As yet, not one person has ever come up with any information remotely backing it up. Like so many myths, it runs on inertia.
A few minutes of thinking about the statistics on things like home ownership, types of businesses, stock ownership, and many other issues would show the number to be complete crap.