I didn't see this discussed in the article, but IMO the main driver is the availability of student loans. When the government guarantees loans, you can lend whatever you want! The price of a TRIPLE occupancy dorm + 7 day meal access is $14,813.29/YEAR at UC Davis. The "meals", if they haven't changed in the last decade, are Sodexo garbage. And don't forget a "year" doesn't count the summer, or winter break.
Students need to decide if a college degree is worth taking on a massive amount of debt. Either we have lots of young people making bad decisions, or a college degree is incredibly valuable. It's not like the terms of student loans are exceptionally great for the students.
Going to college and getting an education (and especially a good university) makes you so much more money in the future, that it's worth paying a lot. Prices could go to $500K and it'd be worth it. Everyone knows this implicitly. That's why immigrant parents nail their kids so hard on grades and to get into a good school. Is it because they want their kids to get a bunch of debt and become unemployed? Come on. You are way way more likely to get a job with benefits, to spend your life doing something more meaningful (however you want to define it).
It's only us who already went to college, got good careers, who are now saying "well college makes you end up in debt, jobless, with a worthless degree. go into the trades. work for the post office." Why don't more people on Hacker News go into trades? Do some unpleasant, strenuous work in dangerous conditions, for about 10 years hustling day and night before your body gives out for $50K/year? Everyone actually doing a trade is encouraging their kids to go to college.
This really isn't that complicated, and I think most people here are overthinking things. A college degree GREATLY greatly increases the chance you're going to have a more fulfilling career easily that makes you back all the tuition money and opportunity costs, and more.