The actual reasons, obviously, are complex and would need several lengthy posts to examine.
But for the sake of continuing the great American mythic structure (that is, education leads to material wealth!), have a look at this map put out by the Washington Post, which tends to correlate college education (or the lack of it) to higher incomes.
Interesting, and slightly depressing, to be made aware yet again of just how poor and how under-educated people in Arkansas are. Some counties have a college degree rate of 3%. And yes, these are the poorest of our counties.
But even Bentonville, among the richest counties in Arkansas, thanks to all that Wal-Mart money, has a median income of less that $57,000/year; and a college degree rate of 36%. (Compare Boston, with a degree rate of 94% and a median income of $127, 000 /year. Or Austin, with a degree rate of 79% and a median income of $129,000/year.)
15 hours ago