Depends on the school. At the University of California, total cost of education (student+state portion) has declined about 25% in real terms over the past few decades, despite an increase in loan availability. Tuition is up pretty much solely due to a decline in the proportion of costs that the state pays, which is made up for by tuition hikes at a rate somewhat less than $1-for-$1.

Some numbers I compiled a while ago: http://www.kmjn.org/misc/uc_funding.txt

The situation might well be different for law schools or other university systems, which I haven't investigated in detail.

But if the decreased state funding had not been accompanied by increased loan availability, the result would have been lower enrolment. right?

Or did I misunderstand what you meant by "in real terms". "in real terms" means TCOE = tuition + state contribution

By "real terms" I just meant that it's inflation-adjusted (in constant 2010 dollars).

I agree lower enrollment is a possibility if there were both decreased state funding and no increase in loan availability. Not sure, though. Would need some information on supply and demand of UC enrollment slots, and what kind of marginal impact loan availability has.

One hypothesis is that it might just result in a wealthier student population with lower average grades. That scenario would happen if there currently exist students who didn't have good enough grades to make it into a UC, but whose parents would have paid cash out of pocket to attend, if their sons/daughters were able to get in. Those potential customers/students who are willing and able to pay, but are currently being turned away, might pick up the opened slots, if any materialized. I don't know how many such students exist, though.

Another approach could have been for the UC system to lower enrollment on its side, so they could educate fewer students at lower tuition, given the same amount of state funding. But California law doesn't currently permit them to do that: the UC system is required to open admissions slots equal to at least 12.5% of in-state graduating seniors.