The culture of the US could be described many way because we are so multicultural. One of the aspects of American culture that has lured so many people from all of the world to the US is the idea that if you work hard you can make something of your self. Which is a beautiful concept. The idea that if you study and get good grades and add value to society you will be rewarded.
Their had always been greed and unfair situations, but it seems that at some point the C-suites, politicians, and the Powers that be, taught the middle class that the lower class of society where the source of most of our societal issues. This position or view shifted the collective attitude of the middle class to view the lower ends of the low end of societal-economic scale with disgust.
And this shifted over the work environment.
The poor are not our enemies. Also, working 70 hours a week might marginally increase your chances of success, but having excess capital to allocate and control greatly increases your chances of being financially successful.