The "Barbarossa" section of the FAQ links to "How critical was the capture of Moscow during WWII? Were the Germans really 1 mile away from essentially destroying the Soviet Union?" .
There, /u/Killfile wrote about the functional reason why taking Moscow would not have been "game over, dude, game over". But that doesn't quite cover the "why": Lord knows that nations have tried all sorts of things that didn't work out as they expected, or attempted goals that they thought better for their purposes.
I find some discussion of that in "Why was Hitler so insistent on driving to Leningrad over Moscow?" by /u/International_KB . It's also covered to some extent in "When planning Operation Barbarossa, did Hitler and German High Command thoroughly consider the failures of Napoleon? Did they plan for similar potentialities?" by /u/kieslowskifan .
This is not to discourage discussion. More questions, data, and debate are welcome. Personally, I'd like to see a more thorough discussion of this.