Tactics are only one facet of what goes into a battle, and are no substitute for all the preparation necessary to win a battle. We all know that the Germans had world-class tacticians - there were none better! BUT they faced logistical obstacles that greatly hampered their ability to win, such as the difference in rail gauges, the failure to prepare winter clothing, the failure to prepare for the Russian winter and the rains that turned the roads into impassable mud. And then there were the strategic blunders by Hitler, who shifted the focus, the emphasis from Army Group Centre to Army Group South and then back again within a matter of months. And another strategic blunder was their terrible mistreatment of the Soviet towns they captured - the Germans were often welcomed with open arms, but as soon as they found out what the Nazis had in store for them, the people turned against the Germans and either joined with or gave logistics support to the partisans...who took delight in disrupting the rail-borne logistics support that was crucial to the Wehrmacht.
If battlefield tactics alone are what win the day, then the Germans would have handily defeated the Soviets. Strategy, logistics, and morale are all every bit as important...and without all these, an army is doomed to failure as Alexander found when he decided to find out what India looked like. History is rife with examples of great tacticians who were defeated by their failure to account for all those facets of warfare, from Hannibal to Napoleon to Cornwallis to our great misadventure in Vietnam where we won every battle but lost the war. The very best tactics are in and of themselves insufficient to win a war.