College debt is getting out of control. I could see MOOCs cannibalizing some lower tier options, like University of Phoenix, which IMO would be a good thing. But I don’t think Harvard’s going anywhere. To become more popular, MOOCs need to do a better job of marketing to employers that their credentials are just as good as some lower or mid-tier state university. Some MOOCs are already doing this, like Udacity with their plans for offline proctoring. For now, most MOOCs are basically TIVO for lectures.
For the most part though, the Moocs' credentials aren't the same as from some on-campus course, and there is not one bachelor program that is fully available from Moocs. Udacity seems to aim at such a credential, but they are at least 75% shy of that.