Russia’s immense size was the biggest factor, the lands the Nazis seized in the early days of Barbarossa exceeded the combined land masses of all the other countries. The Russians could simply fall back behind the Urals and let the Nazis exhaust their supply lines.
Also the tens of thousands of trucks we shipped to them. Allowed them to have motorized logistics while the Nazis largely relied on horse-drawn logistics. That magnified the distance problems for the Nazis
“Russia’s immense size was the biggest factor, the lands the Nazis seized in the early days of Barbarossa exceeded the combined land masses of all the other countries. The Russians could simply fall back behind the Urals and let the Nazis exhaust their supply lines.”
I contend that if America was ever in a land war with Russia our supply lines would indeed be long and of great girth. Nobody does logistics like the American military. We would be moving supplies and war material from Alaska to Siberia, over the Arctic ice to Siberia, up through the black sea in the Crimea, and through the Baltic states into European Russia. We would build roads, bridges, runways, and railroads that they could only envy.