These statements paint with a rather broad brush. There are parts of the US that are so impoverished that it defies belief and more closely resemble pre-industrialization countries than they do what most associate with the United States.
They also ignore that even if other rural areas are technically speaking more rich than the rest of the world, still struggle with an extreme shortage of opportunity, upward mobility, and sense of purpose.
I speak from experience, having been raised in one such area. Had I not moved to a tech hub in search of greener pastures (which is not something everybody is capable of), my life would look so different now as to be unrecognizable. Instead of earning the upper end of the salary band for my line of work with numerous upward trajectories to pursue and a solid bit of retirement stuck away, I'd be working a job earning maybe ~20% as much that doesn't keep track with inflation with zero mobility and an even smaller fraction of retirement funds, and that's one of the best possible outcomes in that region and inaccessible to most.
I've not aligned with the area I hail from politically for a long time now, but clearly it needs help.