Well, lets take my home state of Wisconsin as an example. In 1974 about 44% of the University's funding came from the State. This past year it was 16%. Approximately 10 or so years ago, the total financial encumbrance on a student was roughly 50%. About 4 years ago, when I went back to college, the tuition cost encumbrance on the student had risen to over 71%.
And you are correct, that costs have skyrocketed way more than inflation. But, it isn't so much as it is costs as it is funding.
For every dollar spent in our University system, 7 dollars is returned to that State in increased revenue due to higher paying jobs and new business. For some reason, that fact is completely lost on most people and the State government, especially when you have a former governor that gutted the funding just because he didn't like education.
Edit: Nothing will change until this country figures out that an education is an investment in our future, not a cost.