I believe what Overtonwindow meant was that the cost of education has gotten out of control primarily because whenever the government guarantees debt (cough housing cough) it creates a perverse incentive where the lenders profit by bigger loan values and the schools profit by jacking up the cost of their service for which the loans are issued.

Essentially, there is far less of a check and balance on the price of the good/service. Whenever you have true cost hidden or put way down the road it tends to significantly increase the total cost. Also, there was a hard limit on the cost of education previously because it used to be hard to get a loan for school. People had to actually save money for it, get a scholarship, or pay as they went along. There was a natural limit based on the available money people had available and were willing and able to use to purchase education.

Less than a decade ago (2008/2009) the average in-state tuition was $6,585 for a public school. I graduated in 2006 and this number seems accurate. My undergrad tuition in 2006 was something like $5,500-$6,000. Based on data from the College Board, the inflation factor for 2008 is ~9.5 (against the reference value in 1978 of 1, when the numbers begin). Which means the average cost of tuition for in-state public schools was $693. The minimum wage in 1978 was $2.65. It would thus take 262 hours to be able to earn enough to pay that tuition. That averages out to a mere 5 hours a week! And that's the worst case scenario (making minimum wage). Using the 2008 numbers, the minimum wage was $6.55, so it would take 3.83 times longer to pay tuition (1005 hours)! And that was nearly a decade ago - it's gotten far, far worse since then. Viewed another way, if the cost of college was subject to the normal inflation that the rest of the economy average, that $693 would be a mere $2,737 for 2008.