Because moving to places with lower cost of living, to speak extremely broadly of course, means less income compared to cost of living, meaning a lower standard of living. But with a guaranteed income, a lower cost of living would always mean a benefit to standard of living.
This is true in theory but not in practice in my experience. I presently live in one of the bottom 5 states in terms of population density and there are multiple manufacturing plants that require no experience, are paying 60k+ for new hires, and are in extremely low COL areas. By the way, they can't find enough people to apply and are having to aggressively advertise to fill entry-level spots. I think the issue is more information asymmetry. If people knew the jobs existed and knew what they paid I'm sure at least some % would be willing to move, but no one discloses that out of that gate, unfortunately.
People are not exclusively driven by economics, nor are they immune to economics. For a lot of people, moving to a place with lower COL would mean giving up community and family in their high COL areas. Those networks provide a lot of security that doesn't appear on the books.
These are quality of life trade-offs that are different for everyone.
Of course, the younger or more flexible you are, areas like yours might be a good opportunity, but it's not a obvious win for every entry level job aspirant.
I think the other problem is what happens next. Without the nexus of a city you are stuck at that place or the 4 or 5 similiar places. Good or bad variety can offer more.
