If they have a bigger bag than their adversary, maybe wars would be shorter since the adversary has to surrender earlier since they can't sustain the expenses.

I see bitcoin as putting a upper limit on how much resources you can spend on war. Similar to the point made by Hivemind Ventures regarding AI and bitcoin.

Doubt it. Humans will war over any resource. All anyone needs to do to fund wars is accumulate a bigger bag than their adversary. Bitcoin just makes the funding source obsolete. It does not stop the funding. As Fallout says. War? War never changes.