The politics of resentment and jealously is a major factor in populist politics, I think. Certainly racism and sexism and homophobia plays a big part, but I've had rural relatives talk about how "unfair" it is that NC cities like Charlotte and Raleigh and Cary are doing so well, while their little towns are dying or stagnant. They even talk about why Boone is doing so well, and when you point out that it's a college town, they complain about how liberal higher ed is now. I don't think you can overestimate the sense of bitterness that many rural Trumpites have that they've been left behind by the modern economy, combined with real envy and resentment of more prosperous urban and suburban areas. Many of these folks could probably live with a national economic collapse that caused even more problems in rural areas and small towns, as long as they could see that urban residents were suffering and hurting too. I've heard rural folks talk about Charlotte the way they talk about Obama or Hillary - as a hateful, despised, frightening thing (they still go to Panthers or Hornets games if they can afford it, of course).
ETA: I should add that many of these small towns bear a large responsibility for their own decline, as they have often been dominated for generations by the same local gentry of a few families that often kept out competition for their industries, so when the factories closed they had no economic diversity at all. Not to mention that many of the folks living in these places fear change, and so are resistant to doing anything that might actually lure new jobs, because that would also lead to an influx of "outsiders".
