I love to watch the postwar movies about WWII — other than Patton, they always show Germans dying by the dozen. It’s a bit daunting to realize that Germany wasn’t fully mobilized for war until perhaps 1943, which was the year of the Battle of Kursk (Operation Zitadelle), the turning point of the Barbarossa campaign, the one that finally broke the Wehrmacht and began the two years of retreat and final collapse. And throughout the war (and WWI before it), Germany was massively outnumbered, and didn’t spend its blood needlessly. The bright spots for Germany were the early victories, when France and Britain collapsed in a few weeks, victories only marred by the German failure to close the bag at Dunkirk. Hitler simply lost his nerve, as he often did. He didn’t like victims who fought back.
Had he not been a complete cipher vis a vis strategy and tactics, Germany would have achieved complete power over continental Europe outside Russia, and over the Mediterranean basin; finishing up in North Africa using the massive firepower and formations he instead tossed into Barbarossa would have resulted in a German-Japanese linkup, a cutoff of the fuel supply to the British fleet, and ejection of what was left of the western allies from the Middle East.
Eventually the UK would have rid itself of Churchill (as it did shortly after the defeat of Hitler) and capitulated without firing a shot. A UK aligned with Germany would have meant no staging area for D-Day, and no support anywhere in the Med or N Africa (the so-called “soft underbelly”). At that point, Germany might still have launched Barbarossa, but waited a few years filled with consolidation of its rule over occupied Europe, mobilization, and preparation.
The Japanese and Russians managed to avoid hostilities until 1945; the US beat Japan in a bit over 3 1/2 years, without the level of commitment it might have had without having to worry about a war in Europe. Take that away, and Japan is toast in a much shorter time frame, and the only large powerful ally the USSR — assuming Germany would have, eventually, launched Barbarossa.
The US atomic bomb would not have been ready for the eventual but sooner denouement against Japan, so it is possible that an invasion of the Japanese home islands would have taken place. More likely would have been a US buildup in an enclave (or more than one) in China, in order to shore up the mostly useless Nationalist army there — it would have delayed the invasion of Japan, but would have reduced the Japanese army available to resist.
:’)