The cuts in state aid were mostly due to the 2008 financial crisis. However over decades, tuition has been rising significantly faster than inflation, while state aid has mostly kept up with inflation.
Furthermore rising tuition is not just a phenomena of state schools. Private universities have seen tuition skyrocket over the decades by similar percentages as public schools, and they never received state aid.
https://badgerherald.com/news/2010/04/07/as-state-funding-fa...
and the cuts have continued, eg a further $250m in 2016
http://host.madison.com/wsj/news/local/education/university/...
* Student loans that cannot be discharged via bankruptcy.
* Student loans that are more accessible thanks to both government loans and lending policies that encourage banks and credit unions to furnish student loans.