"My best guess is that the decline in mobility is due to problems in our housing markets (I draw here on an important paper by Peter Ganong and Daniel Shoag). It used to be that poor people moved to rich places. A janitor in New York, for example, used to earn more than a janitor in Alabama even after adjusting for housing costs. As a result, janitors moved from Alabama to New York, in the process raising their standard of living and reducing income inequality. Today, however, after taking into account housing costs, janitors in New York earn less than janitors in Alabama. As a result, poor people no longer move to rich places. Indeed, there is now a slight trend for poor people to move to poor places because even though wages are lower in poor places, housing prices are lower yet."

 - See more at: http://marginalrevolution.com/marginalrevolution/2016/04/why-is-mobility-declining.html#sthash.vo9r8jxJ.dpuf

Seems like a self fulfilling prophecy, sadly.