It's a reality today that no one can achieve a good job without training beyond high school, and that our economy requires people with this advanced training. This has created an exploding market for college education. Either the government assists lower-income people to attend college, or college becomes exclusively a privilege of the children of the wealthy (and an occasional prodigy who is awarded a scholarship). In the latter case, we lack the trained personnel the economy needs and descend into being a third-world country.
Without government involvement in education, college tuition would be much, much higher, because there would be no such thing as a state school.
In a way, this discussion is not unlike the discussion about universal health care. Those on the right are speaking purely from theory, while those like myself can refer to actual other countries who do things differently than we do, and achieve better results. For example, in France, the tuition cost of a Licence Professionelle (equivalent to our bachelors degree) can be as low as €750 (a little over $1,000), and at a public school never more than €3,500 (around $4,800). Private school costs a lot more, of course. Education, like medical care, should be treated as a basic right.