It’s quite possible that they could have succeeded if not for Hitler’s meddling and overriding his general staff. By September the army was within striking distance of Moscow with little Soviet forces left between them. And Moscow was the key city. All the railroad and communication systems ran through the city. Probably more than any other nation Russia was dependent on what they called “the center”. Incredibly Hitler called a halt to the advance and sent his panzers hundreds of miles south to help take Kiev. By the time they came back it was November and the Russian roads were a swamp of mud, and winter hit shortly thereafter. It also gave Stalin time to bring a fresh army up from Siberia. Even still the Germans almost got there. They certainly could have taken it in September if Hitler hadn’t squandered the chance. Whether the Soviets could have continued effective resistance without Moscow is doubtful at best.
The Soviet Union could have been easily defeated, had Hitler had more of a “Divide and Conquer” approach. There were many Russians would would have fought for the Nazis, if it got rid of the Bolsheviks, but Hitler figured (and probably rightfully so), that he’d ultimately have to fight those Russians as well down the road.
Your argument has many merits, and is even partly valid, but I respectfully disagree with the assertion that Hitler's failure to take Moscow was a decisive mistake.
Losing Moscow would have been a major psychological blow to the Soviets, and Moscow was a logistical nexus, as you state. But if the Soviet leadership had had to abandon Moscow (and they were poised to do just that - with Stalin even pacing back and forth on the train platform at one point [when the Germans were within kms of the capital]), they would have first razed it to the ground, so that it would have been of little use to the German war effort (see the destruction of Moscow of 1812, just before Napoleon's "Grand Army" entered the city). The Soviets could have then continued the war from some eastern province (the U.S.S.R. was vast), and Hitler's supply lines were already overextended - meaning that he could have not continued pursuing them.
I will agree that Hitler's dithering on the issue of Moscow was a drain on German resources, which should have all been thrown into the fight to capture the oil fields to the South.
Regards,