Because that overlooks subgroups giving lip-service to unity while functioning practically independently. Kinda like the United Kingdom with the Queen ruling over a Commonwealth, declaring a single sovereign entity while major components really going their own way and occasionally asking her permission or consenting to her rare decrees; when confronted said royalty will assert absolute sovereign monarchy over a unified "sun never sets" empire, yet nobody seriously considers Canada, Australia, et al anything but independent nations.
That’s the way it is now. Any one of those groups could leave the Queen out of everything if they wanted, now. And they would if the Queen demanded they fire their new prime minister or gave 50% of GDP to Britain or something. So they are separate groups, right?
Freegards