Really? How many people want to move to the rust belt? If you look at any representation of population change by state the northeast is losing population and the southwest is gaining
This isn’t universally true — NYC, Boston, and DC all gained in the last 10 year, and have similarly harsh climates to Michigan. OK, NYC and DC have less strong winters, but still unfavorable to many people.
The problem isn’t climate or location; it’s lack of industry and laws/corruption that don’t favor establishment of new industry.