Some Are Mathematicians, Some Are Carpenters' Wives

One of the myths of our country is the Horatio Alger, rags to riches, anyone can become anything if they only work hard enough story. But I think back to a good friend of mine who quit one job on the East Coast to take a new job in the Bay area, leaving behind a life well constructed. Whenever she got overwhelmed with the "How am I going to start from scratch?" questions, she would tell herself, "Hey, I'm white and middle class in America, everything will be fine." Do we have a de facto caste system? I look at the distribution of education, the segregated way we live, and it certainly seems like we are stuck within our socio-economic pigeon holes. Is social mobility in America real?