It was *economic* strength. The German economy was going to have a hard time against the *Soviet* economy, let alone the western allies.
From 1942 on, the Soviets were producing about ten times as many tanks as the Germans. That kind of difference was going to be hard for even the Luftwaffe to offset.
From 1942 on, the Soviets were producing about ten times as many tanks as the Germans. That kind of difference was going to be hard for even the Luftwaffe to offset.