There's a few other options, such as it levels off. But something must change, whether social or governmental or economic. At the current rate of growth, by the time my kids are of age, four years at many colleges is going to cost a good deal more than my house- each. Which is not to say that can't happen- but if it did, it would go hand-in-hand with a cultural return to the days of college as a finishing school for the aristocrats, and not something normal people do anymore.