Well, it's a bit rough and cold up in the north. So I would go with hard terrain to for farming so less food. Less food less people and smaller cities. Don't know about natural resources and how rich the province is so importing food could be costly due to harsh terrain and reachability. Hasn't there been a lot of fighting too with the great war and what have you. And probably half or more of the children die before advlthood.
Highly disputable defensive reasoning you got there.
200 years have passed.
People get marry, have kids, lots of them, as they used to in ancient times since then kids could be put to good use, i. e., labour force.
Now, restoration magic and various healing cults take the place of your National Healthcare System.
And though the climate is tough, it's not uniformly so. There certainly does not seem to be a scarcity of goods.
LAstly, cities need a certain critical number of services and population to function properly. S
Skyrim's don't have them.
Let's address the final argument: Civil war.
#1 The Civil War, as far as I can remember, is a relatively recent event. The consequences would be felt in 10 or 20 yeras.
#2 In fact, as I travel through SKyrim, there doesn't seem to be a civil war going on. I hardly ever bump into enemy camps, and there's not a skirmish to be seen.