For Victorian Britain: https://upload.wikimedia.org/wikipedia/commons/8/86/Isochron...
Hahahahahahahaha! You're funny, if not naive.
"Queen Victoria, Chinese Gordon is on line one. Shall I tell him to hold?"
Collapsed eventually.
Collapsed immediately upon his death.
I mean, the Soviet Union eventually collapsed, and that wasn't because of communication delays. Everything eventually collapses. But "stood for centuries, despite the communication delays" kind of disproves the hypothesis. (Or if it doesn't, given the things that collapse after centuries without the communication delays, it means the hypothesis has no predictive power.)
I think the same argument for Canada applies to Australia: there must be a critical mass of well weaponed insurgents before the time delay makes too much of a difference.
Dinosaurs lasted 179 mil. years. The Roman state, between one and two thousand (depends on how you count).