In America, we believe that anyone can grow up to be anything. You want to be president? Go for it. Among recent presidents, Barack Obama, Bill Clinton, Lyndon Johnson and Dwight Eisenhower all came from modest backgrounds.
Of course, not everyone will be president, which is why, for most people, one litmus test for how well America works is whether they rise above their parents economically.
Guess what? The long-term trends here are surprisingly good. In the shadow of the Great Recession, that's a refreshing contrast to the prevailing gloom.