Even economists recognize the huge social value of an educated workforce
Economists (admittedly the most dismal of scientists) refer to the social benefit of college as a "positive externality," a concrete, measurable value far beyond the dollar amount being payed, that flows to everyone.
You, me, and everyone else gains from each student attending post-secondary school. Making college free, or more affordable, would be a huge win for our country. It's not just some liberal feel-good thing...it's good economics.