I don't disagree there are all kinds of problems. But how does this initiative address any of the financial pressures? It does nothing to reduce the cost structure of universities; in fact it increases the cost structure by adding another thing their professors and administrators must do, not instead of but in addition to everything they currently do. And yet, it does not provide any new revenue streams to pay for that. At least, it doesn't unless there is a payment from Coursera to universities as part of this deal that hasn't been announced yet. My guess is that they're hoping to use it as an advertising loss-leader to attract students and prestige. But that would mean doubling down even more on the traditional high-tuition model, because that's what's going to ultimately subsidize the free courses.
Now if they charged for the online courses, I could see that making a difference in the financial picture. Maybe that's the longer-term plan, for-pay online courses with Coursera and the university splitting the proceeds. That would be closer to the Harvard Extension School model you mention.