By modeling people who were once in your position and have risen out of it.
The vast majority of "poor" have made themselves that way through overspending, under saving, and impulsive poor choices.
I look at the vast majority of my friends -- some of whom make considerably more that I do -- who complain about being poor and living paycheck to paycheck.
I make slightly above that median income of $31,000, in the first graph at the link, and I have a fully funded emergency fund, an investment portfolio, retirement savings, growing college fund for my kids, etc...
I don't live paycheck to paycheck. I live below my means and save or invest the rest. I don't have credit and I don't need it. I don't buy new cars, I don't eat out more than 8 or 9 times a year (unless traveling).
We will always have the poor; some of whom are not responsible for their cir stances. But, I reject the premise that more than a small minority of the 90% (described in the graph) are incapable of surviving on the incomes they make. They just choose to be undisciplined.