As a non-American watching U.S. culture from the outside, I generally agree that those two factors are important contributors to many problems. I would also add to hedonism and individualism the encouragement of a "just-world" myth, which comes as a corollary to the American Dream: you can achieve anything if you work hard for it—therefore, if you didn't achieve it, you didn't work hard enough.

This results in low self-worth of many people in bad circumstances, lack of compassion towards them from those who are better off, and sometimes active disdain from those who were lucky enough to climb out of poverty, as an overcompensation for their own past hardship.