A better theory might be a synthesis of those: it has been a sign of a weakness of the culture produced by the long-term strength of the economy (and which, itself, produces a prospective long-term weakness that threatens to counteract the long-term strength that produced it.)
I know other people that are like me in many ways, having well paying jobs and still choosing to live in the city.
It's not everyone's plan.
Practically speaking, there is nothing sacrosanct about a college degree. It is the educational system, with its bureaucratic filtering mechanisms, elitism, and status-consciousness that has turned it into a humanist sacrament. Education need not be formal for it to be both valuable to the student and the society he/she lives in.
There's plenty of people (blue collar and otherwise) that succeeded with only (or even without) a HS diploma that don't undervalue education, and they don't meet GP's description of the meatheads he is talking about.
That would be Communist.
And when the country is suddenly not that attractive anymore for some reason, the whole thing collapses like a house of cards.
I'm not saying it's going to happen necessarily, I'm just saying the system is dangerously tuned to extreme levels of high-performance / high-risk.
When the engine in my Honda Civic will eventually fail (after many decades probably), it will just stop working. When the engine in an F1 car fails, it may blow up sending flames all over the vehicle and its occupant.
You completely over-estimate the growth rate of US economy. You have probably read the raw GDP data that doesn't correct the growth rate with inflation which was very high in 1975-1985. (cf http://www.bea.gov/national/xls/gdpchg.xls )
We will be fine so long as we bring in the science and math majors we need to drive our economy. Our own kids can then be overpriced car salesman, barristas, part-time actors, aspiring playwrights, etc.
From 1975 to 1985, Finland's annual GDP growth rate averaged from 0-2%, peaking at 4%. The U.S's averaged around 5%, peaking near 15% and nearing 10% several years. You can use this site to compare: http://www.tradingeconomics.com/finland/gdp-growth.
Fast economic growth means that education isn't as necessary to differentiate yourself and get a good job.