Also, your narrative explaining why poor people have low human capital directly conflicts with the evidence. It's the hard working, highly stressed, wealthy people who's children are raised well.
https://www.nber.org/digest/jul06/w11895.html
In contrast, the lower income people living a life of leisure are the ones who's children are raised poorly.
http://www.bls.gov/opub/reports/cps/a-profile-of-the-working...
I have no idea what you are talking about with "roof on your head". If you google statistics on working hours (you probably need to multiply annual hours worked and labor force participation), you'll see that hours worked per capita hasn't changed drastically since the 70's.
With enough experts you can prove anything:
http://www.poverty.ac.uk/report-parenting-families-low-incom...
http://www.rochester.edu/newscenter/stress-in-low-income-fam...
It just moves the barrier.
It's the hard working, highly stressed, wealthy people who's children are raised well.... In contrast, the lower income people living a life of leisure are the ones who's children are raised poorly.
To be charitable, I'm betting that "hard working" and "leisure" have special definitions in this context.
By "life of leisure", I mean a life in which one does not need to work at all in order to have the necessities of life provided. This is the traditional definition of the phrase, no?
Also, a person could have a seemingly easy job that pays a lot, or a hard job that pays little. In my view your distinctions are wrung to fit the point you're trying to make.
Basically no one in the US is living at a "bare subsistence level". People with $0 in market income still consume approx $20k/year in the US, which is more than 3x the mean income (after adjusting for cost of living) over here. If $20k is "bare subsistence" then I should be surrounded by at least 500M corpses.
There are barriers to entry. Children taught with care, with consistent discipline, attention, etc. will do better.
When mom and dad are out working and unavailable to lend a hand with homework, children will not do well. When mom and dad work blue collar jobs where they don't use skills that are marketable for the world tomorrow, children are left on their own to do things children do. When mom and dad are angry and bitter because of their misfortunes, children will very possibly be on the receiving end of unwarranted yelling.
Time, stress-free lives, roof on your head -- these are increasingly luxuries that even middle class folks cannot afford. Not having them is the barrier.