In most places in the USA, two married social workers can afford to raise two children without starving. It's only a few expensive areas where this is impossible.

Employers in high cost areas take advantage of the informal subsidies being discussed here to underpay social workers (as well as other socially valuable occupations such as teachers). But that won't change until the workers move away or switch occupations. There's just no incentive for employers to pay living wages as long as workers are willing to accept less.