I have no idea, but at a guess, I suppose the number of people in the country _with easy access to the sports_ is the more important number than the raw population. There's 300 million people in the US but how many of them have access to snowsports?

It might also just be a reflection of the distribution of medals available - Norway has dominated in the cross country skiing based events, but Germany dominates in the sliding events. Between biathlon,cross country skiing and nordic combined there are 26 disciplines, but luge + skeleton + bobsleigh have only 10 between them.