I know that I wouldn't be motivated enough if I didn't go to college, and I also know that the difficulties associated with trying to prove your worth without that formal credential in a society that is heavily credentialist would be a nightmare. I mean, getting into graduate school is difficult enough (assuming you want to become a professional or upper-middle class), and I don't see how anyone could do it given that they require people to have letters from academic sources as well as the undergraduate degree. Even if you're a genius, they'd still probably throw you in the discard pile. When things are that competitive, there are loads of geniuses out there- the problem is practical concerns.
And what if you wanted to work as a professional without a professional degree? Good luck.
I would agree that college degrees are unnecessary for many people. We know that many people get jobs after college that do not require college degrees. However, I'm fairly certain that you will never rise past a certain point in organizations unless you have the appropriate credentials (not to mention networking). You will never be a lawyer without a law degree or a doctor without a MD or a high level manager without an MBA.
So really it just depends on the person and what they want to do with their life. It seems to me that things will be much easier if you do go to college, even if you incur some debt, than if you don't for the vast majority of people.