Education as signalling

I've been reading a lot of conservative criticisms of the expense of college, including our libertarian friends at Koch George Mason University.  Often they complain that students don't actually learn anything useful in college and that degrees from universities are mostly about signaling who is preselected.

It is strange that conservatives and libertarians, fans of markets, would make such accusations.  Because they immediately fail the test of markets.  If it was true that no value was added by colleges and that employers think that selection process is valuable, then wouldn't employers be recruiting freshmen at colleges?  Why would employers wait and pay a premium for a degree from a university when they can snag those same students earlier?  And wouldn't students bite at the opportunity to avoid spending about $100,000 and earn perhaps $150,000 instead?  Coming out ahead by $250,000 is a good way to start a life.

It's in the interests of plutocracy to place as much of the burden of educational costs in the private sector: that will maximally burden the middle class.  Other wise the upper classes might have to pay taxes.  The middle class is there to be exploited, in their viewpoint.  They may attempt to hide their interests behind banners of "liberty, and hire GMU propagandists to wave them, but we don't have to sit still for it.