Tuning In to Dropping Out - Which educations to subsidize

From the article: "The focus on college education has distracted government and students from apprenticeship opportunities. Why should a major in English literature be subsidized with room and board on a beautiful campus with Olympic-size swimming pools and state-of-the-art athletic facilities when apprentices in nursing, electrical work, and new high-tech fields like mechatronics are typically unsubsidized (or less subsidized)? College students even get discounts at the movie theater; when was the last time you saw a discount for an electrical apprentice?"

That's a really good question. Back when I pursued my undergraduate degree (majoring in a modern foreign language), the state university's budget and sources of revenue were such that students paid about one-third of the cost of their educations through tuition payments. (That percentage has since increased for undergraduates at my alma mater, and of course this leaves aside the issue of who is subsidizing the students' tuition payments.) State appropriations funded by all taxpayers in my state paid for about another third of the university's undergraduate education expenses. (This percentage has decreased since I graduated.) Federal and private grants and all other sources of university income paid for the other third. (The university has since become better at private fund-raising--I get fund-raising telephone calls all the time as an alumnus--and a little better at licensing inventions and the like, but I think has a lower percentage of direct federal grants than it did when I was a student.) If a college education returns economic benefits to a student, and that is the usual claim, why doesn't the student just time-shift those economic returns by attending college with student loans? What is the rationale for public subsidies for university studies, and does that rationale suggest that other forms of studying should also be subsidized? Does that rationale suggest that different college major subjects ought to be subsidized at different levels of subsidy?