To the modern, I would imagine that the purpose of college will be tightly bound to acquiring a job. Of course, the real trick to finding a job out of college these days seems to be being born forty years ago. That said, apparently college grads are less unemployed than those who lack a college degree. However, I think we can trace the link between college education and employment to an over proliferation of occupations wherein some form of college certification has become a de facto (in practice), or even de jure (in law or regulation), requirement for employment. As I noted a couple of posts back, many professions that require such certification could probably be performed by individuals who complete an apprenticeship or some form of non-college training. In other words, having the skills to perform a job has become secondary to having a paper that says you should have the skills to perform a job, perhaps in order to increase the ease of replacing even skilled laborers, as I discussed here.
If we are going to maintain the college framework of job preparation, rather than an abbreviated education followed by apprenticeship, we should probably get something more than employment out of it, to justify the higher costs of going to college. Here we can start borrowing from the historical traditions of higher education. In previous times, a college education was perceived less as a form of vocational training and more as a type of intellectual finishing school. Arguably, this tradition persists and is evidenced in phenomenon such as requiring all bachelor degree seeking students to take a smattering of core courses from a wide range of subjects or requiring all doctoral students to, ostensibly, have a passing familiarity with at least one foreign language.
Justifying the increased cost of a college education through the value of a well-rounded academic experience in the tradition of historic academies seems to be the most obvious method to do so. As I indicate in my Three-R's post (which I still think is one of my best posts), thinking is not a simple undertaking, a college education provides students with practice thinking, fruitful avenues of thought to pursue, and exposure to previously suggested answers to the, thus far, timeless questions asked by humanity.
Although anecdotal evidence is not a sound foundation for statistical conclusions, it does provide evidence of something that actually happened (on the other hand, who actually has the average 2.54 children?). Personally, I have never been terribly concerned with fitting my college education to a specific career, considering I studied philosophy and ended up in grad school I'm sure this is a huge surprise to you. If I end up as a clerk in a used book store or a hobby shop, jobs I could do without a college education, I will by no means consider my education wasted, nor lament the years I spent attaining it. Rather, I hope to keep pursuing education, in whatever guise, for the rest of my life.