Remember how quick WWII was supposed to be?
Within hours of war's declaration, all those deadly accurate surgical strikes with poison gas by massed fleets of heavy bombers ('that always get through') upon civilian cities (who 'always panic and surrender') ?
Japan's lightning war to successfully force America to grant it 'living space' within most of the Far East ?
Germany's easy conquering all of the USSR to the Urals, before the first snow flies ?
How USSR's massive armoured forces on its borders would quickly defeat any invasion by Germany's 'state of the art' puny Panzer Is, IIs and IIIs ?
How Germany couldn't feed its people or its economy so that the British economic blockade, backed by more surgical bomber strikes, would quickly force the Germans to their knees ---- without the need for any British boots on European soil ?
When all Modernity thought about conducting war - that is how it all thought it would go.
Post modern historians - and post modern society generally - no longer sees wars (or any other human activities) as quite that quick and easy....