The Glass-Floor Problem
When it comes to the economic malaise facing America, the biggest problem is not the widening gap between rich and poor, but the stagnation of social mobility. When the income gap of one generation becomes an opportunity gap for the next, inequality hardens into social stratification.
Eliminating the income gap is relatively straightforward (if politically fraught): raise taxes and expand government assistance for lower-income workers. Kick-starting social mobility, once it has slowed, is much more difficult.