I'd make the bolder claim that once it became evident that the Axis was facing a long-war, that the inevitability of their defeat were set. Nolan makes this argument in "The Allure of Battle". Both empires simply lacked the industrial and manpower capacities to sustain their combat losses against the Allies. I'd argue that even after the blitz of Poland and France, the events that followed were mostly inevitable due to the Axis' geopolitical posturing. They were victims of their own fanaticism and delusions of racial and cultural superiority.