Although heavy subsidization is a major enabler of the problem, it is not the only factor. Affordable education is out there. The problem is that people have been conditioned to believe that cheap education is bad education.
The problem is the students have been fed the lie that more "prestigious" schools yield better outcomes. Although this might be true in an extreme minority of situations (investment banking is one example where prestige matters), for the most part, the ranking and cost of the college don't matter at all.
Everyone simply ignores selection bias and assumes that getting into the "best," most expensive school possible will improve their life. In reality, if you control for selection bias, there is no difference between the outcomes one gets from Harvard and the outcomes one gets from Suffolk. In fact, the people who make the most money out of college are community college graduates. (Obviously, this is influenced by a lot of factors, but the blanket assumption that a high-end four-year school is automatically better is clearly false.)
For some reason, no one bothers to actually evaluate the value of their education critically. Instead, everyone simply buys into the collegiate cult of prestige.
http://www.theatlantic.com/magazine/archive/2004/10/who-need...
http://www.huffingtonpost.com/2011/01/03/community-college-g...