What were the economic diplomatic and military reasons for Germany's defeat in World War 2?

Military:

The Wehrmacht (German Army) had attacked Russia in a 3 way attack. Moscow, Leningrad, and Stalingrad. By process of natural selection whereby the incompetent generals die or get captured, General Zhukov emerged from the rubble and led the Soviet army to a victory at the battles for Stalingrad, Leningrad, and Moscow. That and the winter forced the German retreat and the Soviets never stopped gaining ground until the war ended.