Once the Treaty of Versailles was ratified, World War II was pretty well inevitable, in my opinion.
I agree. It carried lessons for the future that I don't think have been well understood.
Alas, you're quite right. I believe it is in
Busman's Honeymoon that Dorothy L. Sayers mentions the Allies' being able to whistle for their reparations, because Germany didn't have the money. And she was writing in the '30s--in the book before, a character was actually able to say unironically that "what this country needs is a 'Itler."