When looking at military history, I always find myself thinking everything is possible. That being said, it seems more possible that Hitler could have won less. Hitler was lucky to get as far as he did.
They often enter the Battle of France into military computer gaming systems. These are the gaming systems that real generals use to sharpen their strategies. Modern generals always do far better than France did, and when opposing modern generals leading France, do far worse than Hitler did. If France had modern generals, they (with some help from the British) could have won WWII in the first months of the war. I do not blame the French generals for not being modern generals. Modern generals learned from watching the French generals fail.
French and Polish generals were OLD. There was no concept of retirement in either country's military, and there was strict seniority. That meant that many of the generals were 80+ years old, and some were 90+ years old. These are generals who were too old to see combat in WWI. They had a pre-WWI view of combat. USA, UK, Germany, and Russia all had one way or another of getting rid of old generals. US retired them. Russia killed them. US General Pershing lived through WWII, happily retired.
Russia was big enough that they could learn from their mistakes. While France was wiped out within 6 weeks, Russia could hold out for years. It was just about area and distance from Germany. The Germans were not going to make it to the Pacific quickly. This gave the Russian generals time to learn how to be modern generals. Even before the war, they had Deep Operation, which was a more complete modern strategy than Blitzkrieg. With time, that was generally accepted, and they started winning the war.
On the other side of the world, the USA far from Europe also had time to learn modern strategy. The Germany's lead in strategy had completely vanished by the end of the war.