The logic of this made some sense at the time; very high tuition subsidies were a gift to the upper middle and upper class -- few poor students went to college back when subsidies were high. Ideally, states would have continued to fund higher education, and the increased tuition would be used to support lower income students. But the states took the money away from their universities in bad times, and did not replace it -- in my state (Virginia) it went to prisons and medicaid.
There are lots of other problems with student loan statistics -- it is true that the current student loan program has been a tremendous boon to for profit colleges and trade schools, which is where most of the default occurs. And the media likes to publicize the outliers; the average debt at public universities is about $26K, at private non-profits $31K.
But the overall cost of higher education has only slightly beaten the cost of living (and has certainly increased less than health costs); the price has gone up because students are responsible for more of the cost.