You had better look at what happened in late 1917 and 1918 when Czarist(Communist) Russia dropped out of WW I with the signing of the Treaty of Brest-Latovsk. It enable the Kaiser to re-deploy his army from the East to the West and we had mega trouble until late 1918. Hitler would have done the same thing in WW II.
Actually,some people need to recognize that the American army fought only a small portion of the German army,and our men ,were not supermen either.
I concur with the poster that IF Hitler's army had defeated the Soviets the world would be a very different place today.
Ultimately it was Hitler's insanity that lost the war for the Germans:Hitler exterminated millions of loyal,or at worst indifferent polically,Jews who could have contributed mightily to an "ordinary" war effort,he failed to utilize the strong dislike of the Czechs,Ukrainians, and others and turned down the certainty of another 500,000 or more soldiers fighting against Red Russia...in all Hitler was NOT a brilliant leader,just a vicious demagogue bent on destroying those who didn't worship him.
I don’t think your analogy holds up at all. The allies were essentially exhausted by the time of the Bolshevik coup in November 1917, and yet with the addition of the doughboys in 1917, the allies were able to turn back the desparate gamble, and last ditch effort of General Ludendorf. Yes, we defeated the vaunted German army, even with the collapse of the eastern front precipatated by Lenin’s strategic surrender at Brest-Litovsk.
As for the Germans hooking up with the Japanese, a lot of good it would have done, since the Germans were essentially bled dry by the Russian red army, and would have surely faced unrelentless guerilla warfare from the partisans from the Urals to Vladivostock. And don’t worry about the Japanese, my father’s boys and the rest of the heroic American Navy, Marines, and Army service men in the Pacific theatre would have taken care of Japan, whether Hitler was able to resupply them or not.