The Union was never losing, only at risk of losing. The odds were on their side the whole time.
Not true for WW1 and definitely not true for WW2. If soldiers ever lacked for weapons it was due to logistical problems in getting the weapons to them NOT because they didn't have enough weapons to begin with.
USSR had superior manufacturing capabilities as well major support from USA. They also had superior numbers and as the war progressed the technological edge of either powers' armaments swung back and forth, always in contention. One thing that remained stable though is that German engineering tended towards more extravagant weaponry and that's what's earned them the myth that they totally had the Soviets outclassed techwise. Soviet weaponry for it's part was robust, easy to repair and easy to manufacture.
But still inferior. German weaponry, artillery, and armor outclassed the Soviets, and the combined factors of hostile terrain and sheer numbers are what ended up winning the day for the Soviets, who while possessing a robust manufacturing base, did not have enough armaments in the beginning of the war to equip all of their men. The Soviets spent the blood of their people quite recklessly.
