Despite Russia's vast industrial and military improvements during the course of the war, Germany's raw industrial production still outmatched them virtually 'til the very end. The biggest reason Germany had trouble matching Russia's quantities of tanks and weaponry was because it focused its efforts on developing fancy new weapons systems instead of perfecting the mass manufacturing of existing systems, which is what the Russians tended to focus on with systems like their famous T-42 tanks.
I've read that the USSR, for all its seemingly endless supplies of resources, labour and troops, was damn near exhausted of its supplies by the end, and the only reason it didn't collapse was because they were able to recruit fresh troops and labour from the territories they liberated as the Germans withdrew. Without the western, Italian and North African fronts for Hitler to worry about, and no western aid or assistance to the Soviet Army, Stalin didn't stand a chance despite all the stupid mistakes on the German side. For all the glorification of the naval war between the US and Japan, I've heard something like 90% of America's military industrial resources were actually spent on the war in Europe.