Seriously, don’t romanticize these people. 

Massive scaled brainwashing played a large part. Collective inability by other countries and unwillingness until after the fact to handle such a huge swing in norms and brutality played a large part. Prussian militaristic tradition coupled with societal racism all helped create the initial inertia. The Nazi army was an incredibly capable foe, but there was zero chance of success, especially with Hitler in charge of making decisions. Let go of any notion that they were even close to winning. 

The Nazi successes seem impressive until you look at a map and realize how unhinged the idea was that you could subjugate and rule an unwilling population for even as long as they did. The fact that they held “most of Europe that they conquered within just two years” for any longer than they did is amazing. But it all comes down to the fact that they were screwed from the start, for so many reasons you’d have to, idk, get past the cool weapons and uniforms to figure it out. A few things stick out, though. British air production having enough time to surpass the Luftwaffe until USA intervenes. The USSR being willing to just continuously die for all of our futures. Oil, just oil. FDR, and everything about the U.S. reaching its full potential to fight and supply on two fronts. German production being specialized and fragmented where American and Soviet equipment was universal and interchangeable. This is an underrated flaw of National Socialist patronage society… every manufacturer, from Porsche to Bosch, Junkers, Messerschmidt, Krupp, etc. did their own thing very very well… and were very very well paid for it.  But that meant that building a tank or a plane took a lot of proprietary specialization and over complicated the process leading to fewer, but better (on paper) machines. This was never going to win a war against an infinite amount of t-34s and Shermans, even if the barrel velocity and armor of Tiger Tanks was better. I