I still say, if the Nazis took Moscow, Stalin would have been deposed, and someone more pragmatic could have taken control, who knows perhaps even allowing non-Bolsheviks into the government and a greatly changed post-war Soviet Union.
I don’t think taking Moscow would have made any difference. They have lost Moscow before, so that wasn’t a new thing for them. Sort of like when we lost DC to the British, didn’t slow us down a bit. I think like they did under Napoleon, relocate somewhere to the East, and keep fighting. The Germans always believed grabbing important cities was way more important than it really was.