I think it's due to the fact that no one stays with the same employer for more than four years. Back then, you could look forward to a decades-long career with

I think it's due to the fact that no one stays with the same employer for more than four years. Back then, you could look forward to a decades-long career with the same company (my father-in-law was with IBM all his life) - you joined Dow out of university and could expect to stay with them for 20 years. But who would even consider moving to Midland, MI nowadays? It's a godforsaken place an hour north of Flint! You can't risk buying a house in a one-company town! So we all submit to the Boston or Bay area commute madness.