Some part of that is also due to the changing demographics of the school. In the 1970’s, about 80% of the undergraduate students at U of M were from in-state. Now, that number has fallen to about half. In-state tuition is less than a third of out-of-state tuition.
Certainly states have cut back support for colleges, though. But that doesn’t change the fact that college costs aren’t still increasing faster than inflation. Adjusted for inflation, college costs roughly the same today as in 2006. Skyrocketing college costs appear to have been a limited phenomenon, for about 20 years from the mid-1980’s to the mid-2000’s. The next 20 years were a time of pretty stable costs. I suspect that will continue for quite a while going forward.