>>314771598The big reason is a good portion of the scientific community was disgusted with what they were doing and just left. It was a major brain drain whether Germany wanted it or not.
On top of that they were simply unable to beat the British. Add supplies from overseas, local resistance movements in all of the occupied territories, no powerful allies with interests in their area (Japan wasn't going to get involved in a European land war and Italy's troops were not well supplied),research divisions competing with each other for funding, and every practical weapon design outside of small arms (like strategic bombers) being scrapped in favor of weapons that fit Hitler's ridiculous strategy.
Then he picked a fight with the Russians. He thought he was fighting a bunch of backwater Slavs but instead he was fighting a country with a great industrial capacity than his own who designed weapons that were more than a match.
Then you bring in the US. Say whatever you want about their direct contributions, but they were logistics masters. Couple that with the Brits abilities to protect convoys and bam, a deadly combination. On top of that they brought lots and lots of very durable trucks to move all those supplies.
The only winning move for Germany was to not start invading the UK's allies. That was what spelled disaster.
