Richard Florida uses this as another example of the increasing wage gap in the US. People in the bottom of the list are twice as likely to be getting by with incomes of less than $35,000 than people at the top of the list. That makes a huge difference to a community. I think it's just further example of how policies that have their roots in the Civil War continue to cost us. Every single metropolitan area in the top ten in this list - from the ones in Texas to Georgia to Louisiana to Arkansas to West Virginia - is in the former confederacy. Every single metropolitan area on the bottom of this list - from Manchester, NH, to Washington, DC - is outside of it.
There are really just two ways to explain why some people are poor and some are not. One is to look for differences in their situation, using something like a pareto chart to understand the impact of parents' income, community investments in education and private investments in capital, etc. In this approach, generational wealth and income are subject to forces that can be manipulated and changed through policy and private action. Another is to say, "Well, some people are just like that." Under this umbrella lies belief in aristocracy, celebrity-worship, racism, and a shrug of the shoulders about differences, a weird sort of acceptance of life's inevitability (or even God's will). It's no coincidence that the former Confederacy is - to this day - a place where poverty and poor education is more rampant than in any other in this country. Racism is, of course, the ultimate belief in one's helplessness to change realities like income disparity.This region has been very reluctant to let go of its racists beliefs. (It wasn't until February of 2013 that Mississippi officially abolished slavery.) It's still a place that rejects policies that would change incomes as the intrusion of "big government." A goodly portion of the south is still accepting of poverty and shrugs its shoulders about why some people are poor. In their minds, little can be done and so little is done.
I think it would be worth tracking two economies as we seek to understand what's happening in the US. I suspect that tracking the former confederacy and the rest of the country separately would yield some interesting data that would help to make policies on both sides of this (still big) cultural divide.