It's really hard to create a fully-realized bubble given how separate the two campuses are, but I think it can still work. The bigger challenge is making something work without taking anything away from the North Campus. They need South Campus to stand on its own while still keeping USF, IOA, and CityWalk just as relevant. They don't want to accidentally split the resort in two.
But as far as creating the bubble goes, right now, it’s not fully there. Give it 10 years of hotels, expansions, and more Universal-exclusive experiences, and it may look and feel a little different.
The whole “the bubble pops once you’re in a car” argument only really applies if you’re choosing to drive, and I would bet a good chunk of on-site guests won’t be, instead opting for on-site transportation.