I think that in the long run wider societies need some shared belief system / culture / ideas to function properly, just like all kinds of communities do in sma

I think that in the long run wider societies need some shared belief system / culture / ideas to function properly, just like all kinds of communities do in smaller scale. Essentially we are tribal animals, and nothing can really change that. Without a sense of common identity there's little solidarity, and without solidarity you'll eventually have conflict. Failed states with civil wars tend to be those which lack any kind of common identity and ideas, while more successful ones tend to have those.