If Ritzhardt is really a noble, why would he live like the Sami people traditionally (he doesn't even have a Sami name)? You'd think he would live in more comfort, still possibly owning a large number of reindeers, but having others handle the animals. He might be participating in the fur, lumber, gold, and other such businesses. Also, the population shouldn't be dropping, unless he only meant the precise corner where he's living. I guess that might also explain my first point, if he was given some godforsaken place to look after, and lots of people moved elsewhere, chasing development and better prospects.