Germany made the same mistake that Rome did - the did not pull back their soldiers and resources and spread themselves too thin, which inevitably lead to their downfall.
@Justicar The funny thing is Germany had the munitions, equipment and supplies needed for the Eastern front, but they lacked the needed logistical skills to actually transport them. While Germans were dying, their much needed supplies were sitting in warehouses 100s of miles away. Which reinforces the adage "Amateurs study tactics; Professionals study logistics"
@Mike_Microwave @Justicar - Hitler hesitated at Moscow. Germany didn't provide any winter gear (presumably in denial that they would even need it). They left the incompetent Goering in charge of the Luftwaffe.
They did learn some lessons from WWI. They took Norway, so the fleet wouldn't be bottled up. They took France much, much faster.
But sadly, they didn't learn enough.
@Mike_Microwave @Justicar - Honestly though, I blame Woodrow Wilson.
Germany should've won WWI. The US shouldn't have joined that. Germany could've pulled it off back then. And as a bonus: There would be no "Holocaust".