Obviously nothing is “free.” Somebody is paying for it, which I assume is the students who are taking classes at MIT for their actual degrees. MIT isn’t going to undercut itself, so there will always have to be students paying the big bucks for the big degrees. And those students will demand that their degrees are worth much much more than the free online courses.
knowledge has always been free for the taking, and, with the internet, more is available than ever before, the problem is that few have the drive or ambition to take it and learn it.