Yes, College Has Overwhelmingly Been Worth It for Americans. Why Do You Ask?

Note that unless you think the income distribution is "optimal", there are powerful positive externalities to funding more people to go to college even if the marginal individual is making a rational benefit-cost decision.

And the numbers very very strongly suggest that many, many people deciding not to attend college have not been making rational benefit-cost decisions:

http://priceonomics.com/is-college-worth-it/: