This chart points out one of the interesting things about the poverty level in the US-it has not always decreased since the War on Poverty started.
Part of the issue is that less of American’s yearly income is protected from income tax. Another issue is that wealthy people are paying less of a percentage on taxes of their income. But the primary reason may well be that wages have not kept up with inflation in most jobs.
Americans like to harken back to the days when they were younger, and prices seemed less, without figuring inflation into the mix. But along with prices inflation, there has not always been a sufficient growth in wages in many jobs. The minimum wage of $1.35 an hour in 1972 projects to be $7.66 in 2013-about where the minimum wage is today. Working people who earn the minimum wage today are not receiving any more real wages than they did receive in 1972.