The main reason Adolf Hitler lost World War II was because the Wehrmacht initiated Operation Barbarossa too late, letting the severe Russian winter catch up, hindering the German forces from launching the final assault on Moscow. Not being able to finish off the Russians early, the German forces got bogged down on the Eastern Front, wasting precious resources and protracting the fighting. This gave the Allies time to land on North Africa and then on Normandy and to increase the bombing raids over Germany, which led to a multifrontal war, exhausting and crippling the German factories weapon output capacity and logistics. The real culprit of this delay and the unexpected awry development of war events was Benito Mussolini’s failure to invade and defeat Greece in time to secure the southern flank.
The Italian Army had begun the invasion of Greece on October 28, 1940, but it was repelled by a Greek counter-attack, forcing both forces to wage a long war of attrition. By late March 1941, the Italian troops were still in trouble, unable to advance an inch. Thus, Hitler decided to intervene to secure the southern flank of the German offensive against Russia because by this time British troops had already landed in the Balkans to shore up the Greek Army in their fight against Italy. Since Greece could be a springboard from which the Allied forces could launch a northward offensive against Germany, Hitler began the German invasion of Greece on April 6, 1941, to protect and shield Germany’s southern Front. The Wehrmacht’s 12th Army quickly crushed the Greek resistance, but delayed the initiation of the German attack on the Soviet Union, known as Operation Barbarossa, as it had originally been planned to be launched in early May. Due to Operation Marita, which was the code name for the German invasion of Greece, the German invasion of the Soviet Union was postponed until June 22, 1941. Had it been launched in May, the German forces would surely have captured Moscow on time before the arrival of the Russian winter and the Siberian Armor division, under Zhukov; the extremely low temperatures froze the armored vehicles fuel as the artillery pieces breeches got stuck with ice and could not be used.
Had Germany defeated the Soviet Union early in the war, it would have devoted and concentrated most of its military resources in Western Europe to avoid any Allied landing by reinforcing the German navy, and with it the German submarine campaign in the Atlantic.
Another reason for Germany not winning the war against the Soviet Union was that it lacked enough long-range, heavy bombers to attack and destroy the Soviet infrastructure and armament factories lacated in cities lying far beyond the enemy lines, such as Samara, Saratov, and Omsk. As the German forces advanced eastwards, many Soviet factories were simply dismantled and shipped to the eastern regions, where they were assembled again to start turning out large quantity of war materiel.