I am assuming that when you refer to WW2 you are including the war against the USSR, and you're referring to the idea that the Axis powers never had a realistic chance of achieving victory in the East. I'll point you in the direction of a few answer's /u/Elm11 has given on the Red Army before and during Operation Barbarossa that touch on that idea while covering other topics:
How vital was the arrival of troops from Siberia to the of Defence of Moscow in WW2? - this answer also goes into detail on the incredible Soviet mobilization capability. The Red Army's nominal size nearly doubled - 5.5 million to 9.5 million - in the first week of the war alone.
Soviet industrial might between 1940-1945? - answers what it says on the tin.
I have read the book most commonly referenced in these answers - Operation Barbarossa and Germany's Defeat in the East by David Sathel - and my understanding is that Barbarossa was an overly ambitious campaign that failed despite near ideal conditions for it to succeed. The planning for it was very poor and intelligence gathering was bad as well. They severely underestimated the ability of the USSR to replace and reinforce lost divisions. It began to dawn on certain commanders in late August and September, as did the significant losses they had sustained in achieving their great victories.
"Doomed from the start" might not be completely factually accurate but it is probably a closer approximation than the myths believed in some areas that if they had invaded a couple of months earlier or if Hitler hadn't been a control freak, they would have achieved victory. Again, I would encourage you to read those three linked answers (particularly the first) as they give a very solid answer to your question.