Ah, good point on why we should look at employment vs. unemployment. Makes sense.

I was tempted to argue that the decline in construction doesn't support the "obsolete jobs" hypothesis, because the jobs were created by an overheated housing market and shouldn't have been there in the first place. But regardless of whether the jobs were justified in the first place, they're not coming back. A technological shift isn't the only thing that can make a job obsolete; a one-time speculative bubble can do the same thing.