Yes indeed, by the time the Western Allies invaded Normandy the war had been a Russian mop up phase for a year and a half. I think the only way Germany could have gotten out of the war intact would have been to sue for peace during the phony war, after the German/Russian "partition" of Poland and prior to invading France and starting the air blitz against Britain. If Hitler hadn't declared war on the United States following Pearl Harbor there would have been on one to invade Normandy in June 1944 and all of Europe could have ended up behind the iron curtain. And with the economic power of western Europe to fund them, the USSR might still be in business even today. Interesting to speculate about, but history is what it is regardless...