The states with the lowest SPM poverty rates are midwestern states with large rural populations, like Iowa and Nebraska: https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ.... (California's poverty rate is almost double those states'.)
The unemployment rate in Iowa peaked at a little more than half the national unemployment rate in 2009-2010.
As noted at your link, many of the extremely poor rural areas skewing the averages are Native American reservations. How do you propose to make them relocate to cities?
Here's coal mining in the US, over the last 35 years: https://fred.stlouisfed.org/series/CES1021210001
If they don’t have the money they should move, possibly with assistance. I don’t see any case for subsidizing services in places where it really expensive to provide those services. Why that’d be like government grants to rebuild houses on a flood plain that got flooded out.
Labor shortages are a critical problem in many of these communities. Young locals often move to the cities and rarely move back, and while automation has helped support the local industries it has not nearly covered the shortfall. Much of the working age labor that does move into these areas is either illegal immigrants or ex-convicts looking for a fresh start. Due to shortages, minimally skilled physical labor often commands 3-4x minimum wage in my experience.
It is a mistake to think that people want to be rescued from these areas. Maybe some do but most have reasons for living where they live.