Specifically, was there any indication that the Arms Industry would have difficulty maintaining the Wehrmacht, Waffen SS and Luftwaffe during the earlier French and Polish Blitzkriegs? In comparision to the Russian invasion, that is.
For extra points, could someone provide a English-Language source of production output for the industry? In terms of spare-parts and vehicles in particular?
According to Ian Kershaw in "The End" production went up during the war. Speer was able to work miracles in moving production and workers around and was able to, even while Allied bombing went up and Goebbels kept stealing his workers for his own crazy plans to arm the populace, to increase production. German production only crashed when the Allies took the factories and the resources off them in the final months of the war in 1945.