Limited resources: Germany is, after all, a country. Although there are many subordinate countries such as Romania, Finland and Italy, anyone with a little knowledge of World War II knows that the quality of soldiers, weapons and equipment and fighting will in those countries are poor. Although it is not negligible, it is not far behind. Germany has the eastern and western fronts and the North African battlefields, and the resources for fighting with the allies at the same time are definitely not enough. Especially strategic resources such as rubber, steel, gasoline and so on.

The incompetence of the top: At the beginning of World War II, the Germans won a great victory by relying on the suddenness of Blitzkrieg. At that time, the German high-level officials were carried away by the victory and made many extremely wrong decisions, most of which were made by Hitler's obstinacy and not listening to the military's opinions, just like the success of the British Dunkirk retreat, the premature opening of the Soviet-German battlefield and the wrong judgment of the allied landing in Normandy. By the end of the war, Germany was defeated like a mountain. Under the command of Hitler and other high-level officials who did not listen to the opinions of the military, a series of inexplicable battles were launched. The famous ones were the Battle of Kursk and the Ardennes counterattack, etc. These huge failures of the battles that should not have happened were caused by excessive consumption of the already scarce war resources.

In fact, the German army is not as powerful as it is generally believed. Until the opening of the Soviet-German battlefield, the German army never fully mechanized. Many troops' artillery was pulled by horses. It was not that the German army could not be mechanized, but the huge war consumption prevented them from being fully mechanized. The strength of the Germans lies only in their advanced concept of war, and "Blitzkrieg" is the best expression of this concept. When tanks were used as infantry support weapons in Europe, German armored forces had thoroughly understood the real use of tanks.