I looked for tuition costs over time, but didn't find much online. I did find Stanford tuition data going back about 100 years. Here's a graph of the log of Stanford tuition over time [1]. The log of tuition has grown pretty much linearly.

There doesn't seem to be much difference between how it grew before government backed loans and after them. Somewhere I've got a spreadsheet where I compared the growth rate to the inflation rate. I can't find that right now, but if I remember correctly the tuition growth rate was about twice the inflation rate.

It would be interesting to get this kind of data for a variety of schools, but I couldn't find it.

[1] https://imgur.com/fXnjDNn