I agree with OP in some general sense in a closed political ecosystem because WWI/II didn't happen in a closed ecosystem. The extremes were just enough that it couldn't be easily contained within their perspective domains or countries. I wasn't aware of apt analogies before reading this thread but I just called it the Champion's Paradox, that with enough wins a fighter generally becomes less vigilant, "decadent" if you will, and I'd wager that the same holds true for larger domains as well given that all other things being equal.