Is there any evidence to that? There is no way anyone could possibly survive for a year (outside of a third world country) on that. Those statistics likely include students working part-time etc...
On $50,000/yr? Lots and lots of households are doing exactly that, yes, especially if we're calling that after-tax income. But no, not by spending only 15% of their income per month. More like 100%. It'd take 15% of $50k just to rent a barely-livable old, rotting single-wide and a lot way outside the city to keep it on, before any other expenses like utilities or food or transportation, and this is a pretty low-cost area.
In my friend group at least three families (two with kids) are making under $50k pre-tax income, as households. A couple others are a little over it but not by much. There are three with household incomes way over that and... go figure, each has one tech-sector worker in it. Age ranges of something like 25-36, none in college.
I like to point people towards Malcolm In The Middle. It's actually a very optimistic take on the struggle for a vast swath of American families; certainly not an exaggeration of the difficulties.
I think you misread the person you're responding to. The average isn't 7.9k, 15% of the average is 7.9k - they are implying that the parent commenter makes far more than the average US household. (and further down, the OP states that their yearly income is ~360k, which pretty clearly demonstrates the point)
In my friend group at least three families (two with kids) are making under $50k pre-tax income, as households. A couple others are a little over it but not by much. There are three with household incomes way over that and... go figure, each has one tech-sector worker in it. Age ranges of something like 25-36, none in college.