Does Mass Production Requires Mass Consumption?

Emmanuel Saez, the professor of economics at University of California at Berkeley, has updated data on income inequality in the U.S., full summary here (HT Paul Krugman). Click on chart to enlarge.

I am keeping in mind the reasons of global crisis ... and marginal propensity to consume.

Mass consumption is not maintained via borrowing, so the ability to consume is impaired ...

Let's pray for wealthy to pull the rest, and supply side economics will do the miracle?