The Germans lost WWII on every tactical front, for reasons that are blamed on der Furher to just dumb luck on the part of the Allies. They lost due to poor aircraft, they lost due to poor tanks, they lost due to poor shipbuilding, they lost due to poor logistical planning, they lost due to manufacturing bravado. Before anyone says “Hey the Tiger Tank kicks butt, or the Me262 was the best plane in the world” please note that mistakes related to those very items caused the failure that was in the works when the Invasion of France too place. Wrong conclusions were drawn from early victories and it cost them quite a bit.
Poor Aircraft - The Me109 was equal to the Spit I only at the beginning of the war. It was on its heels from that point on. German bombers were terrible. The Stuka was obsolete in 1939 (did you know it had a top speed of 187 MPH?).
Poor Armor - 37mm cannon on the PzKwIII couldnt not kill French Tanks. Only 40 tanks were upgraded to 50mm guns for the invasion of Russia. Tigers (PzKwVI), Panther PzKWV) were not tested properly and were trounced at operation Citadel (Kursk). Did you know Hitler demanded Tigers stick together with no infantry support? The Tigers also did not have MG’s on board at that time. The Panther had awful transmission issues early on. These problems were solved, but it was way too late.
Shipbuilding - Bismark, need I say more?
Logistics - Africa, Eastern Front (Stalingrad), Battle of the Bulge….common theme?
Manufacturing - War production was almost completely stopped in December 1941.
Many people take pride in what the Germans did, but the more I learn, the more embarassing it gets.