(2) After a year of this, the wife has a baby and works just 20 hrs a week, still at $15/hr. The husband has been promoted to store manager or higher (convenience and fast-food store chains are desperate for workers they can promote) and makes $25/hr.
(3) Their new combined income is $67,600--less than before, but still enough for a good life except in a few megalopolises. This is a completely realistic scenario, and not even demanding (the husband could easily continue to work 48 hrs a week). And it's been done with jobs at convenience stores.
(4) If you come up with places where the starting wages are lower, they're highly likely to be in poor states where the cost of living is lower. It's still a realistic scenario. Making enough money to support a family is easy in the United State if you're willing to work. Easier than it was in the fabled 1950s.
He's an economist? Damn that's incredibly sad
If you think that part of his work is bad, you should read his interviews about his time in Thailand, where he supposedly did some work on behalf of the American government on how to pacify a restive native population (in Thailand, these were the peasants and ethnic groups that got displaced to build western-accomodating hotels and resorts, and in the US the population were the african americans in the inner cities). Mind you, his trip to Thailand was before the Vietnam war even started IIRC, so he literally just went there to do experiments on racial control.
Actual demon of a human. And he seems to be a very big star with rightists. Go figure.