There's another interesting similarity not discussed in that autoworkers in, say, Wyoming, were pretty thin on the ground and not so well paid. In the Detroit area, sure there was competition and excellent pay. But in rural Wisconsin there was one (of many) rural assembly plants. Pay wasn't awful, but it wasn't as amazing as working in Detroit. And there was "a" plant. You get fired, you better move out of town because there is only one employer (now zero)
In the same way, if you're a software dev, yes, you can get eight times the average salary in two geographic areas where the cost of living is only ten times higher than the rest of the country (LOL). However, outside NYC / SV... pay is still good, although lower, and jobs are Extremely thin on the ground. Your average non-coastal grad is more likely out of the field (UPS, starbucks, unemployed) or at a helpdesk or admin doing non-dev work, not actually slinging code as an actual dev. If the schools insist on slurping out a couple hundred grads a year, and there's only a couple software dev positions total, you do the math. If anything, the concentration is even more intense in software development than it was in automotive manufacturing. GM had a major plant in a podunk city in a podunk county in rural Wisconsin, well, at least until it closed. Wake me when Google, YC, and Facebook open branch offices in rural Sparta Wisconsin.
I believe this is a large part of the lack of interest. 99% of the country desires not to live in SV or Manhattan, therefore the lack of interest in becoming a developer.
I would agree with the legendary enrollment oscillator theory having seen innumerable cycles inside and outside CS. Everyone knows there's infinite demand for new nurse grads everywhere in the country for decades, right? LOL tell that to my cousin's newly graduated wife.