On a lot of forums,a lot of people are unable to grasp the reality of 1941,being educated with things as C3,Desert Storm,wars without big casualties,covered by CNN,with wargames,etc .
The Germans were realistic :it was impossible to conquer European Russia in a long campaign (even in 1944,the Allies needed 10 months to eliminate Germany):in a long war,the SU could mobilize millions,what Germany could not ,and,this would be the decisive factor .
The only possibility was to destroy in a short campaign,the standing Soviet forces,which were located in the western parts of European Russia,hoping that,meanwhile,the SU could not mobilize and send to the front new units.
After this short campaign,which,following the Germans,would result in the collaps of the SU,light armed and mobile units would advance as quickly as possible to the A-A line,only hindered by sporadic resistance of local fanatics,the A-A line had to be reached before the winter,even before the autumn.The Germans had to be in Moscow before september,because,what some people do not grasp,Moscow is not located in the middle of the SU,it is a city located in the western part of European Russia:the distance from Brest-Litowsk to Moscow is some 1000 km,and from Moscow to the A-A line ...also 1000 km,and from the AA line to the Urals ...again 500 km. Imagine the allies arriving (after 10 months of bitter fighting )at Berlin (Paris Berlin :1000 km) and discovering that they still had to go 1500 km eastwards .
As such;the importance of Moscow was minor .
Transposed to 6 june 1944 ,the Allied strategy would be :destroy in a few weeks the German armies in Normandy,and than,full speed not to Berlin ,but to East Prussia,the goal being to be in Berlin before september,in East Prussia,before november .
All this in the hope/assumption/wishfull thinking that meanwhile the Germans could not mobilize new units,but that in the summer the Third Reich would fall apart,and that there only would be local resistance from fanatical Hitlerjugend boys.