I learned absolutely nothing during my 4 years of undergrad that is practically useful to my current vocation, and I can say the same is true for 90% of my peers.
For some areas of study, college IS worth the cost. For example, hard sciences. But, for the vast majority, it's not (think: business and administration, art, history, economics, etc.)
I would guess that in 90% of cases, graduates would be more valuable to companies and potential employers if they spend those 4 years and $300K (tuition + lost wages) learning/practicing their specific trade/industry.
So, when are we as a society going to realize that 90% of us are wasting 20% of our most productive years on useless learning? This really seems like a travesty to me.