Well, that's half of it. To my understanding, college used to have more focus on simply becoming a more rounded, worldly individual. If that is your goal, the value of big name schools drops precipitously. It's the perception of college as the next level of education requisite for a job that increases the value of big name schools and leaves individuals weighting expected salary increase vs. tuition.
It probably isn't anything devious- no matter what you believe about higher education today, I think most people will agree that as human knowledge has expanded, so too has the amount of education required to perform and compete in cutting-edge fields.