Cause or effect?

The first thing I thought when I saw the graph was that the cities with the most college graduates per capita were also the most expensive. Could it be that college graduates are the only ones who have earned enough to afford these places?

Also the idea that (CollegeEducation = SmartPeople) is really played out. Many of the smartest people I know have achieved great things in spite of or instead of college. Finishing college is as much a matter of determination as "smartness", whatever that means.