just google "human wave doctrine" or play hearts of iron 3 and you understand why the allies/soviet union won the war.
Hearts of Iron 3 is subject to significant axis-favored game balancing for purposes of multiplayer as well as to make up for it's inability to realistically simulate the fall of france through other means. The Wehrmacht often simply bashes it's way directly through the Maginot line, and even when it attacks Benelux usually just advances forward in a line, not attempting any encirclements and allowing the allies to retreat in good order. Had this moronic battle plan been attempted in real life, the Germans would have played right into the Allied hands, been unable to sustain it's war industry and collapsed by 1942-3, even without soviet assistance.
If you want a realistic simulation, try
Gary Grigsby's War in the East: Don to the Danube. Adam Tooze's
The Wages of Destruction is a good illustration of the economic problems facing the Reich and illustrates quite well why the German war effort was doomed to fail. With all that said, I think you're being awfully dismissive of the Allied efforts in the war. They did not simply zerg rush the Germans with densely packed infantry. It's particularly insulting to the Soviet forces, who executed some of the most brilliant offensives in history in the final years of the war to decisively crush the German war machine.