Whilst I agree that Eastern Russia was underpopulated and with poor infastructure (which hurts both sides) I will completely disagree with the tech part. The Russian Armor completely outclasses the Japanese in every era of the war. In fact, Russian Armor outclassed everybody but the Germans. Russian Support weaponry were literally the best at the time and the infantry were also better equipped than the Jap infantry.
Early war USSR armor: KV1 (1939, completely immune to any Jap gun), T34 (1941, massively produced and better than every Jap Gun), KV2 (1942, completely immune). While the Jap tanks could easily be penned by anything with 50 or more mm.
Early russian support: ZiS2, ZiS3, DDShK, BM30. The greatest shit.