It was at least partially artificial. The GI Bill post WWII introduced millions of families who otherwise wouldn't have gone to college the ability to go to college. This set off two cycles, one of which is now those folks who went to college on the GI bill wanted to encourage their kids to go to college, which is well and good, but it also showed the economic value to a bigger mass of the country of going to college. Now that made its way into government policy as a result, so the government took steps in the 1970s and 1980s in particular to expand collegiate enrollment, which drove up the price of college which lead to Clinton signing a bill that gave us the student loan system as it exists today, which then fed even more enrollment as a matter of policy, but now universities too were in on the game, as that money is guaranteed which lead to bigger recruitment drives.

I'm giving a very high level synopsis here, but the snowball effect wouldn't have happened without the policy interventions by the government, in particular the student loan shenanigans