You make a good point but when the technology a person was focused on goes away, what then?
People need to take seriously the threat that tech change poses, and plan a major career move. How serious is a person about making a change? Doe he/she want an uncommon skill? Then move to China and teach English. (Easy, get TESL cert and someone will probably pay your way. Stay a few years.) Need a college BA or law degree? (Easy; online colleges for both.) In the wrong city? Go where the jobs are; tell spouse to sell house and follow if you land a good one.
If I were not busy, but had a decade to spare and a compliant spouse, I'd probably go to China.