Colleges are focused on teaching kids content, not on teaching them skills, and too many students are focused on passing the multitude of tests in the multitude of classes they take, rather than really learning.
I think this is a broad generalization, but not without truth. I was fortunate in many of my undergraduate classes and most of my graduate public policy classes to be taught how to draw connections between unlike facts or theories, how to write clearly and succinctly, and how to think critically. Without a professor who emphasizes the development of those skills, however, students must rely on their own initiative to apply lessons beyond the immediate content.
A strong liberal arts core can develop those skills, but a series of general education requirements with no connection to each other entrusts this skills development to professors who are not often asked to focus in skill development (and some of whom have never thought much about pedagogy in their own academic path).