The mass surrending and deserting was rare in the russian army because if caught by the Germans chances were you were killed and if caught by the russians you were most def killed for treason. The German defeat is because of multiple reasons. Hitler being one of the bigger ones. And most soviets would not have co-operated with germans nor would germans be willing to co-operate with soviets. But had Moscow fallen and the government been de-centralized then the USSR would have most likely gone to civil war and negotiated a peace with Germany. It was Hitler who wanted no peace with Communists he wanted them dead which was why his goal was to first find the Soviet army and eliminate it. But Other German high command like Bock, and Guderian insisted on taking Moscow in an effort to split the soviet union as this was the only way the Germans would be able to avoid an ultimate defeat in the long run. And even more German Commanders had a completely different view of everything. As for casualties they are not 100% accurate and therefore only general things can be implied from them like The russians had more soldiers, and the Germans killed at a higher rate.