Size, yes- population is less than half of the US population. I might remind you how the US and allies won WWII- our manufacturing, having been unaffected by damage from attacks, was able to shift from consumer goods to military and while US manufacturing is far from what it was, it can still produce a lot of goods, if needed. Who makes materiel for the US military? Most is still made here. Subassemblies may come from other places, but we still have the most aircraft, missiles, largest navy, etc. Look into the assets that are mothballed, waiting to be recommissioned.
If their Military Industrial Complex is so huge, why haven't they squashed Ukraine like a bug? Why did they bring NK into it? Their people are tired of what's happening, too.