First, about half of people that go to college don't graduate in 6 years. That means the asset isn't upgraded but the costs and loans still live on. http://www.slate.com/blogs/the_slatest/2013/02/27/college_co...

Second, the very idea that college "upgrades" the asset is specious at best. http://www.amazon.com/Academically-Adrift-Limited-Learning-C...

Third, people with degrees do earn more, but remember that they actually take four years or more off. That's 4 years of taxes and raises that the government doesn't get. Given wages in a lot of non-degree jobs that don't require degrees (public employee unions and public safety work come to mind), this is not an insignificant amount.