Many American people don't feel especially "rich" at the moment, but if you look at the most of the Earth, America is rich. In detail, for most of human history, poverty has been the norm. What did America and other rich countries do that the rest of the world didn't?
Two things: they offered their nationals rule of law and economical freedom. Countries that leave their people free to develop property, start businesses, and trade in a secure legal and political environment are blessed with prosperity. You can glimpse this in the Economic Freedom Index compiled by the Heritage ...