you should check out what happened to steelworkers when the mills all moved to cheaper places.
As for retraining, I am skeptical. I think it, at best, puts an older demographic in competition for entry level jobs, and generally at a disadvantage[2].
[1] https://www.census.gov/data/tables/time-series/demo/geograph... [2] https://www.theatlantic.com/education/archive/2018/01/the-fa...