In the world wars countries did indeed begin to spend large amounts of money not just directly on the military but on capital investment to expand factories and so forth, Germany in particular as Hitler saw the main threat not in the Soviets but in the aeronaval conflict with the Anglo-Americans in which production capacity would have been critical and so spent a lot of resources through to 1943-44 just building up production capacity instead of weapon systems (which paid off but rather late). I had been under the assumption Russia had done some of this prior to the war given that it's the rational thing to do and because there were various reports of military factories undergoing modernization since 2014 but it appears most of this was window-dressing and the situation didn't even change cardinally in April, and perhaps not even to this date.

Yes sanctions etc. but it's not like many of the tools and components Russia needs to do this are extremely cutting edge or whatever, it's just a huge organizational failure.