the state of the mind of the "true believer" is one that I believe all cultures pass through,

If by that you mean it's a phase they pass through and then it's done with, a sort of societal equivalent of adolescence, I think that's over optimistic.

Analogies between individuals and society are occasionally helpful, and frequently seductive, but they need to be treated with extreme caution.    The more relevant analogy for true believerism, I suggest, isn't so much adolescence, it's fever. By that I mean, it isn't something a society gets over once and for all, it's something that can strike again, maybe in some new form.