(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.