You are absolutely correct that geography and climate do not justify Russia's relatively low population. Russia has fertile lands and other natural resources. Economy alone does not explain low population either, since most of India lived in poverty for the last few hundred years, while enjoying significant population growth. For the last 90 years, Russia had decent basic medical care (mass immunisations, medical checkups for secondary school students, etc), so thas is not an issue either. Below I am going to list several issues in the decreasing order of their impact on demographics
