From: El Paso, TX
After an event happens, it's easy to go through the list of actual occurrences and point to the important facts. But before Barbarossa, Stalin was looking at a lot of others, and in his mind these were the important ones:
- The Red Army had clobbered the Japanese in Manchuria just a few years earlier, and suffered few casualties in so doing.
- The War in Finland wasn't a great success at first, but the Soviets "muddled through" and won in the end. At no time were they seriously threatened with an actual loss.
- The conquest of Poland, and the subsequent occupations of the Baltics and Bessarabia were all cake walks.
As for the German Army, Stalin felt that it's results were magnified by the incompetence of it's opponents, and in particular that none other than France were remotely comparable in size and weaponry. But on that count, the Soviets clearly outclassed the Germans:
Tanks: 14,000 to 3300
Aircraft: 9000 to 2000
Manpower: 3M Soviet troops in the Baltic-to-Black Sea theatre alone, a number that Germany couldn't remotely approach
Now those are just raw numbers and don't account for differences in quality and tactics, but even there the Soviets had encountered German weaponry in Spain only a few years earlier - and had visited German factories - and they weren't that impressed. Even the outmoded T-26 had proven superior to the German Mark I and II, and if German equipment "won out" in Spain, the Soviets felt it was only due to superiority in numbers, something that would not be true in a mano-a-mano encounter.
I think we can all agree that Stalin was drawing the wrong conclusions and vastly over rated the ability of his forces, but that's really the whole point. Stalin believed what he wanted to believe and there were just enough facts readily available to convince him that he was right.