I’m going to go ahead and take issue with this statement that poor people are not succeeding because they lack self-confidence, don’t know how to behave, and settle. While I do believe these can be issues for the poor, this viewpoint is similar to Ruby Payne’s take on social class which has been widely criticized. The first thing it does is stereotype the poor. There are most certainly people who have been advantaged their whole lives who don’t manage to pick up the skills they need.
In addition, poor and working class people are not accidentally “lacking” these forms of social capital you list. There are deliberate methods of education that teach working class schools rote learning, while upper class schools are learning critical thinking/problem solving. See an excellent book by Brantlinger for more on this. The social skills that are necessary for middle and upper class jobs are not superior skills. They are cultural norms that are considered by many (including me) to have scores of issues (e.g. lack of honesty, too much distance, lack of camaraderie, inflated egos over being “professionals”).
Just as the low wages of the past 30 years have harmed average American pocket books resulting in “financial literacy” popping up as the cure to fix those broken people who “can’t manage money,” we find people looking for ways to blame inequality on the poor. It’s their deficits. It’s their lack of hard work. The hardest working people I’ve known in my life were working class. They died young. Their bodies eaten away by their efforts. I just hope this fantasy that “successful” people have about making it without a high degree of luck is shown some reality.