Haven't thought about it, kudos for taking a longer-term view :) But your scenario requires that some sizable majority of people share the same sentiment. E.g.

Haven't thought about it, kudos for taking a longer-term view :) But your scenario requires that some sizable majority of people share the same sentiment. E.g. the idea of "world proletarian revolution" rests on the assumption that the majority of people are workers who will be more loyal to their class than their state. On the other hand it is entirely possible for most people to be more loyal to numerous hypothetical global communities which are too small to oppose nation-states. Everything stays the same in this case.