Can you be more specific than just 'rural'? I've been through middle Illinois, Iowa, Nebraska and Kansas and those areas seem mostly fine to me. Is it because rural farming is still ok but other rural like appalachia or rural Montana isn't doing well? Specifically where is hollowed out?

I took a road trip through the Northern states, WI, MN, SD, WY, it was truly depressing. Some of these towns were just shells, no interesting businesses, tiny run down houses, shuttered buildings, the only buildings that were open were the post office and a couple diners or gas stations. I don't consider that mostly fine, it was sad.

I think OP was probably referring to the 'dead Main Streets' and 'neighborhood near the plant that closed is totally struggling' phenomenon. I've been around the same areas and see seriously struggling places. When I was growing up, the Main Street was a little better but still bad, but the new strip mall stores/outlets/Walmart out by the highway were doing great. Now, the stores around the Walmart aren't even alive.

I've seen what they described in Texas, Virginia, Utah, etc. I suspect that it is like this throughout much of the southern United States. People are born in places that cannot provide them an adequate living, and then they are too poor to leave. It's a pretty hopeless situation to become trapped in.

Basically a lot of the "rust belt" areas like Ohio, Kentucky, large swaths of Pennsylvania, parts of Virginia, etc., and also rural areas of southern states that were always below average or poor are now downright destitute.