Jeff,

Moscow is not the only railroad hub the Soviets had. It was important but it was one among many and its lost could be replaced by cities further east. To give quietus to Soviet resistance, the Wehrmacht must take or threaten all cities on the Leningrad-Mascow-Stalingrad-Rastov line. If the Germans have only Moscow, they would still face a Soviet industry relocated in the east and would fight the Soviet winter counterattack in Siberia.