On the Russian front this was only true at the beginning of Operation Barbarossa, then it became very clear a year later than the German losses became increasingly in Soviets' favor. Plus Soviets were fighting on their home ground, with direct access to resources, which would eventually turn the advantage on their side. Of course hindsight is everything, but several generals opposed Hitler's decision to go against the Soviets because they knew the odds were against them. So assuming that Germans expected to win is, I think, improbable.
And to come back on the original point, you do War to kill enough people to make your opponent give up or until it is completely destroyed. In the case of WWII, even if Russia kept losing soldiers 10:1 vs German soldiers, Germany would have still run out of soldiers to fight with anyway because of Russia's massive supply of men behind the frontlines - And even if Russia did give up at some point, there would have been no way Germany would be able to control a country as large as the Soviet Union with the army they had on site. Germans were clearly bound to lose no matter what.
And to come back on the original point, you do War to kill enough people to make your opponent give up or until it is completely destroyed. In the case of WWII, even if Russia kept losing soldiers 10:1 vs German soldiers, Germany would have still run out of soldiers to fight with anyway because of Russia's massive supply of men behind the frontlines - And even if Russia did give up at some point, there would have been no way Germany would be able to control a country as large as the Soviet Union with the army they had on site. Germans were clearly bound to lose no matter what.