

By your logic, Canada has twice the population of the US. This is obviously not the case.
Land area has little to do with population as you yourself eloquently show with the examples in your statement. The area’s culture, history, and environment are all more relevant factors for demographics. The USSR’s population was the hardest hit by WWII and their population ‘catch up’ hindered by frequent famines.
Yeah ‘food shortage not rising to full blown famine’ would probably be more accurate. There have been several severe droughts in the USSR/Russia since WWII that impacted food availability.
This chart shows the age distribution: