[dgoldstein0]

Maybe. They had the strategic depth and political will. But that forgets that they had major amounts of supply and industrial expertise brought in from the US. With none of that, perhaps they would've lost Moscow and the rest of the East. That could've given the Nazis significant more supply - especially if they got their hands on Soviet oil in the Urals - would could've made them hard to kick out.

We'll never know for sure.

[senderista]

Well, a lot of that US (and German!) industrial expertise was applied well before the war, in the 20s and 30s.

It's certainly plausible that Moscow could have fallen if Hitler hadn't diverted Army Group Center to Kiev etc., which would have been a major political/logistical setback, but I still doubt it would have changed the ultimate outcome (especially if it had left the units of the Red Army intact that were encircled and destroyed in that diversion).