It occurred to me that the thing about the rich in America isn't so much that there are so many of them (although there are) or that the poor in general are a hell of a lot better off on average than they would be, say, in the Sudan (although they are) but rather that both are the exception to the general rule.
This is a nation of the middle-class, the bourgeoisie, and it has been pretty much since the beginning. The people at the extremes of the income curve are just that, extremes, and not at all representative of the country as a whole. It's worth noting that the one time in our history when the curve got seriously warped (the Depression) that aside from a few intellectuals and oddballs, nobody bought into the ideologies of Communism or Fascism. Communists were frustrated that the American labor unions didn't become hotbeds of Communism as they did in other countries: union men saw themselves as being in the middle class already, with their children able to move into the upper class by becoming lawyers, accountants, doctors or joining other professions. Even now, most of the poor and homeless are what they are because they screwed up, made bad choices, are mentally ill or have fallen prey to one or another addictive chemical.
So where are these "two Americas"? Scattered throughout the one true America, isolated patches within the bourgie nation - or, more accurately, on the mythical island of Antilia with the Cross of Gold and other such fables.