Appalachia is overwhelmingly white, made up of a large number of rural towns separated by mountains. The rural, white, moderate good old boys of yesteryear in the Democratic party have become just one faction of many, as Democrats have become the party of diversity, of tolerance, of progress, and of science.
So while the Democrats of yesteryear could help the average Appalachian find a good-paying government job, they're now seen as anti-job as they've been trying to drive the country away from a coal-based energy plan. Bill Clinton won West Virginia by double digits in 1992, but Obama lost them by 13 in 2008.
Most people of Appalachia stopped their education in high school, so the Democratic message of trying to retrain coal workers into other fields has thus far been a non-starter, as is the Democratic argument for averting climate change. Most Appalachians don't want other jobs, they want the coal jobs to come back. It was a good-paying job that people had done for generations. George W Bush promised to bring them back, as did Mitt Romney, John McCain, and most recently, Trump.
And while deregulation brought a few coal jobs back, the vast majority of them are gone forever. Climate change is going to be an absolute expletive to get under control even without coal, so nobody but third world countries have any plans for its expansion. Trump's sweet lies were just so much more tempting than the stark, uncomfortable truth.
