He's basically saying there's no need to buy food because you can eat free samples at the grocery store. He also just happens to be the author of a "contrarian" book arguing that college is worthless. It's purely a coincidence that he's posting misinformation on the same topic - making claims about a university where he doesn't work - in one of the most widely read news outlets.
Also I think a more obvious example of it being popular is the courses and lectures that are made freely available online.
Or a sign that some people don't understand the value of networking and the value of what earning admission to Princeton signals.
If you are genuinely capable of learning everything alone, just from lectures, there's no need to move to NJ. It's all online anyways.
"...Educational austerity is the simplest path back to an economy in which serious on-the-job learning starts during high school — not after college."
https://www.latimes.com/opinion/op-ed/la-oe-caplan-education...