Per a recommendation in The Week, I read White Trash by Nancy Isenberg. Per a recommendation from galen I read What You Are Getting Wrong About Appalachia by Elizabeth Catte.
Catte wrote Appalachia primarily as a rebuttal of JD Vance, but also as a rebuttal of everyone who has ever written about hillbillies in any capacity including Nancy Isenberg. Which is a shame because Nancy Isenberg's core argument is that "hillbillies" are an artificial construct created to serve racists, eugenicists and social conservatives so that they could compare poor Whites to poor AnyoneElses and that prior to WWI there wasn't any coherent racial or geopolitical organization that matches up to what we call "Appalachia."
The whole point of "Appalachia" is to denigrate it. It's to say "look - my policies aren't just abusive to ethnic minorities, they're abusive to lazy white people too therefore I'm not a racist!" Appalachia serves as a useful literary construct: you can write tales of poverty without needing to delve into the racial issues that cause poverty. Appalachia serves as a useful shield: "Look, I'm not a member of the ruling class I grew up in Ohio which is somehow every bit as deprived as Navajo country."
What struck me hardest about JD Vance was his insistence that he's somehow a member of some historical ethnic group utterly distinct from white trash anywhere else. If you're from rural Ohio you've got ethnographic justifications for everything you do, unlike white people from rural Maine or rural Montana or rural Texas or rural California.
The Appalachian Regional Commission largely exists because of the fucking coal miners, who have lived in a state of perpetual twilight for eighty fucking years. It's a play for "I'm white and poor, but somehow distinct therefore give me money." The reason we're still talking about this shit is as a region, appalachians lean into the stereotypes.