NO_one, you forget Parkinsons Law: "Work expands to fill the time available to perform it."
I guarantee you that, not only will existing CASA jobs remain if GA was to disappear, but the staff numbers will actually continue to expand!
You think I'm joking? For my sins I was once a group general manager systems integration in the IT world and I've seen Parkinsons Law at work first hand!
https://en.wikipedia.org/wiki/Parkinson%27s_law