America and the Soviet Union had close to the same amount of people in them. But the amount of Soviet dead is many times that of American dead.Obviously somebody had it wrong. Stalin could have kept the Germans from Soviet borders but he was bending over backwards to appease Hilter while he was purging his army of its talent! If he had not invaded Finland and revealed to Hilter what a mess he'd made of things by his tremendous losses to Finland Hilter would have left him alone.
Read "Mein Kampf". Hitler's goal was to create "Lebensraum" in EASTERN Europe -- all the way to the Ural Mountains. He was basically ready to de-populate the area of slavic peoples, whom he considered to be inferior, and replace them with Germans. Hitler had no intention of doing this sort of thing in the West, though he tinkered with the French frontier a bit.
It had a lot to do with the fact the war was fought on Soviet soil and the Nazis were exterminating the population in the occupied areas.
The winter came a little early in 1941. Stalin was also fortunate in that theJap[anese decided to fight us rather than attack his possessions in the Far East. Once the Japs were committed to a war against us, he could move huge reinforcements to the defence of Moscow.
But to give thwe devil his due, after December, 1941, he seems to have made all the right moves.
Also you can note that Hitler delayed Barbarossa in order to deal with the uprising in Yugoslavia. Had Hitler not done this he may have taken Moscow in July or early August.