When John Hennessy gave his talk on MOOCs at the CRA Snowbird meeting he recommended the book Why Does College Cost So Much? by Robert Archibald and David Feldman, both economics professors at William and Mary. I've never seen a good answer to the title question so I read through the book. To overly simplify their main thesis: It's not that college has gotten more expensive, it's that most everything else has gotten cheaper. Technological advances in manufacturing and shipping have made greatly lessened the cost of goods, and the rate of inflation is calculated based on a basket of goods. So service industries, particularly those that require highly educated people and don't benefit directly from technology, look expensive in comparison. College costs closely map to medical and dental expenses, and closely followed broker expenses until technology made brokerages cheaper.
Archibald and Feldman even argue that there isn't a college affordability crisis for the majority of Americans: They are still better off than 30 years ago even if we take out college expenses. Hardly the doom and gloom scenario that Hennessey was portraying.
Their main point is that one cannot increase the number of students to faculty without decreasing the quality of education. That's where MOOCs come in, supposedly the solution to allow faculty to be far more efficient in the number of students they can teach without reducing quality. Might help control college costs but could harm research at top tier universities and many other universities might cease to exist.
Alas perception is reality and the public sees college expenses growing dramatically compared to the general cost of living and blames wasteful spending at universities. Curing this "disease" might kill the patient.