The other issue is the that level of consumption of everyone in every household income quintile in the United States has steadily been going up (in a way not fully reflected in the consumer price index or other gauges of consumer behavior), so almost everyone has more stuff, more space, and more comfort and health than people in the "same" income quintile did in my childhood. There may indeed be some structural, societal problems caused by uneven income distribution (what I have liked about the United States and Taiwan, the two countries I have lived in the longest, is that they have tended to have better Gini coefficients
https://www.cia.gov/library/publications/the-world-factbook/...
http://hdrstats.undp.org/en/indicators/161.html
than some other countries around the world), but there will ALWAYS be some people who make more money than some other people living in the same country, and the main issue is to help each country and all the people living in each country gain prosperity over time, which has been the general worldwide trend.
http://www.theworldeconomy.org/
http://www.economist.com/node/18679001
To reply to a question in another comment below:
So the working class has been taken to the slaughterhouse?
No. Americans of all income levels still enjoy unparalleled prosperity compared to most people around the world, and the high rates of voluntary immigration into the United States even from countries that are themselves prosperous show that something about the overall mix of living conditions here isn't "slaughtering" people but rather meeting many people's aspirations on balance, in some way that makes moving far away from home an appealing idea.