I don't believe that is actually how tribalism works, as a mechanic, that it's simply a subjective identification with an abstract collective. (Peak liberalism!) I think that genuine tribalism, as opposed to just postmodern identity-starvation, is built on personal and usually face-to-face interactions, around shared places and rituals. The most passionate football fans regularly attend matches, or supporter's pubs, they may even be members of organised fan clubs, and that gives their identities a robustness and endurance that, say, people who felt the N64 was better than the PS1 didn't turn out to have, because their identification was much more abstract and flimsy. The word "tribe", here, is important, it's not (well, not just) a relic of Victorian racism.
How far does that apply to the nation-state, and how far can the nation-state be explained in those terms?