The key being "supported" - that definition has changed dramatically in the past 50 years, and what you're referencing in the US was the middle class, not those living in poverty (then or now).
Strangely, there has been a negative correlation between increased worker productivity and the amount of work required to support a family.
I wonder where did all that surplus value go? Is it a coincidence that inequality has raised in the last decades?
> what you're referencing in the US was the middle class, not those living in poverty
There is no middle class, only proletariat and bourgeoisie. Either you own means of production or you don't.
The proletariat could afford a decent lifestyle without living paycheck to paycheck until a few years ago, but not anymore.