If that happened, California could take the money they aren't spending on the UC system anymore, and decide just to fund research directly, setting up a state research institution that isn't a university. Maybe they will; I have no idea.
I think you and the grandparent both seem to be arguing that "removing the undergraduates and sending them to MOOCs" will somehow change the character of the way "academia" works, and that's what I just don't see. Undergraduates are a side project at these schools -- as mentioned, they don't provide meaningful funding (tuition breaks even at best). And at most, they provide a cheap labor pool for the research programs. Take them away and you'd never notice the difference.
You mean like this? http://en.wikipedia.org/wiki/King_Abdullah_University_of_Sci...
$10 billion endowment: http://www.npr.org/templates/story/story.php?storyId=1204482....
Obviously details matter. A university in Riyadh is going to be disadvantaged vs. one in Palo Alto, but the idea that professors can be encouraged to move by big paychecks shouldn't be controversial.
US academic institutions are dominant because they have more money (largely because of historical government policy), not because of any monopoly position enjoyed over the students. I can certainly see European or Asian institutions taking over this lead, but certainly not because students want to attend "MOOCs". If you want a top-tier university go and buy one.