The cause is probably the other way around: college has become a necessary (but not always sufficient) ticket to the middle class, and so (by this calculation) is no longer valuable for its own sake.
I agree. In the past, there were fewer people with university degrees so they were worth more. Humanities degrees were seen as a indicator of intelligence and accomplishment. Now they are seen as an indicator of someone who went to university but had no real idea of what he wanted to major in.
