This is the Good Savage myth. Tribal warfare were pretty common and before nation-states humanity were in almost perpetual war:
https://scribe.rip/m/global-identity-2?redirectUrl=https%3A%2F%2Ftowardsdatascience.com%2Fhas-global-violence-declined-a-look-at-the-data-5af708f47fba
The only issue is that modern warfare is highly industrialized and therefore more deadly. And since war is costly in terms of resources, that's why a bitcoin standard would make them impossible.