If the USSR was organized like the US, they wouldn't have had 1/3 of the country die, and they wouldn't have had to have 10-1 advantages to win battles.
The USSR was lucky to survive WW2 at all. They did almost everything they could to lose the war, from purging almost all the competent officers to allowing basically the entire army to be destroyed in Poland. If you took the USSR, and swapped in a democratic government in 1920, they would have escaped the war with 1/10th as many casualties. Maybe they would have surrendered, maybe they would have never been attacked, but in the end the 22 million extra people who died would not have had to.
Your argument comes down to 'only a dictatorship can throw 1/3 of the population into a meat grinder while the others quietly watch' and I'm saying 'only a dictatorship can do that, but only a dictatorship ever has to do that'.