The Germans would have had to leave more than half their Army in Russia in order to secure it.
That’s my view, anyway.
L
Germany had half their army fighting Stalin on D-Day, so if they had not been pinned down in the east, Hitler could have made the Allied invasion much more costly. But thats just ‘what-iffing’ on my part.
Operation Barbarossa proved Adolf really didn't understand maps with regard to distances, that lines on the map indicating roads were not much more than dirt tracks unsuitable for fast mobile blitzkrieg, much less the necessary continued vastly stretched out supply tail, and was unaware of Russian winter conditions on the ground.
End of June was the delusional start of the Eastern Front campaign fueled by the rapid Western front conquests through well developed road and rail networks which were non-existent for all practical purposes beyond the Polish border in Russia. Even today the Russian paved road network is a joke compared to Western Europe.
Even in the event of success of establishing a defensible border for the occupied territories, his attitude towards the Poles and Slavs guaranteed wide spread insurgent within those boundaries requiring almost an equal amount of troops as needed to protect his new boundaries against Russian counter attacks. And then there remained the southern oilfields.
One has to wonder if he wasn't was using the same methamphetamines as issued to the Wehrmacht and SS troops. His explosive tirades, paranoia, and great delusions about the actual physical conditions of troops and the civilian population argue that drug abuse might well have driven him beyond real expectations.