Already there are more American men on disability insurance than doing production work in manufacturing.
There is also this:
The determinants of levels of consumer spending have been much studied by macroeconomists. The general conclusion of the research is that an increase of $1 in wealth leads to an additional $.05 in spending. This is just enough to offset the accumulation of returns that is central to Piketty’s analysis.
That is from this very good Summers review of Piketty.