I don't know, maybe no more war? Ok, that is naive...

While I do understand your argument as relevant, I think when individual rationality stands against collective rationality, you should always pick the individual rationality if possible. The other way around, you only risk being exploited by those who decided themselves for their own good rather than the collective one.

It's a problem without general solution, but only partial one, so take the one that is the most beneficial to you.