Education and upward social mobility used to march in lock step--as the phrase "education and social mobility" implies. I think the real question is, "What kind of education leads to upward social mobility?"
We live in a world that increasingly views a traditional liberal arts education as irrelevant, and most students who enter the university and community college systems seem to be aware that their paths to upward social mobility lead not from the study of English or history or philosophy but from business administration and "change management" and mechanical engineering. As I write this, I am aware that my definition of "education" places me among the Luddites, but there I am.
If it is still true that education leads to upward social mobility, I would argue that this paradigm now excludes (ok, my arguments are reactionary) education in the liberal arts. My belief rests on many years of teaching English composition and literature, during which I have seen my students' abilities to read and write, as well as their desire to read and write, drop to zero. Very few students would include reading and writing as part of their approved curricula. They now view English (and history, philosophy, sociology, art) as a necessary evil--an unavoidable General Education requirement--that will get them closer to courses that they believe translate to higher incomes, which will, in turn, lead to upward social mobility.
I suppose that "education and social mobility" are still loosely related, but I am not sure what that "education" really is.