Both my kids went to UIUC and we paid about $15k/yr, and both my kids graduated within the last couple years. And UIUC isn't a Directional State University; it's the flagship of the UI system. You can just look this up: tuition numbers aren't secret.
You just cited the out-of-state cost of the flagship state university in Illinois as if it were the in-state cost of a Directional State University in Illinois. Again: you have an argument here that depends on people not Googling list prices (the prices that nobody actually pays) and seeing what they actually are.
They in fact differ wildly between students and between colleges! UIC and NIU are commuter universities where students generally don't live on campus. Students at UIUC live in campus-provided housing for their first year, but not generally for subsequent years. Everybody, whether they're in school or not, pays for housing. So no, the cost comparison you're offering here is not very useful.
Shortly later
I also think you might have to ask around to find a student paying full price for books.
