How do you inexpensively scale the personalized work done by professors and TAs in grading your work, making sure you're not cheating or plagiarizing, and clarifying your misunderstandings when you're not "getting" the educational material? If a firm hires someone with a degree, what they're paying for is knowing that a person actually learned the material, which requires human intervention to do grading and to prevent cheating. That costs a lot of money, because technological innovations don't really make the grading or cheating prevention any cheaper. Education is the prototypical example of an industry affected by Baumol's cost disease.

The cheapest part to scale is the educational material and lectures, but that's always been the case, even before MOOCs. It has been possible for more than a century to go a library for free and get access to more educational material than one person could read in a several lifetimes. What has never been cheap are teachers who care, and I don't think that MOOCs can technologically innovate so much so that they reduce the cost of a teacher that cares.