I bring this up because often liberal arts degrees are predicated on an assumption that a person will be seen as more than their degree, even in the labor market. That is, someone who can complete a liberal arts degree in philosophy with good grades and the right extracurricular experiences, who has taken a lot of the right coursework, can go on to get a master's in computer science, or biochemistry, or a law degree, or MD, or learn the right skills from their employer.
What we have now is a problem where too much focus is put on certification. Employers (or their HR departments?) see a degree as a certification to do a particular skill. They don't want to try to surmise these skills from other experiences, or to train new employees in those skills, they want a box checked that says "this person can do A."
This I think is the source of this trend more than anything. It's an equating of degree major with skillset, or ability, or whatnot.
When you live in a society where having X degree is required, either by employer hiring practices or by law, as a certification of being able to do A, B, or C task--even if you do not actually need that particular degree to do those tasks--you are inevitably going to see everyone want to have X degree. When you create an economic environment driven by rent seeking and regulatory capture of one sort or another, you're going to see people try to position themselves accordingly.
I think the rise in interests in MOOCs, etc., and criticism of traditional educational structures in part is a response to this overcredentialing. The irony is that the liberal arts degree, which is supposed to be a kind of happy medium, kind of has been squeezed out from both sides of that argument.