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.