Going from poor to rich isn't really whacked, it just doesn't happen often (but it does happen). What's whacked is that you can be a sellsword, with lots of experienced, be poor, find a way to make quick cash, but you're the only one who ever figures out how to do it. I understand it can be hard to code the AI to respond to your sneaky tactics of killing dragons from far away using a paralysis spell tied with an ice spell or something, but if you're picking up 2 or 3 dragon bones from a huge dragon skeleton beside a khajiit caravan, why aren't they selling the rest? Then again, why aren't you taking the whole thing?
I always assume that RPG villagers are very very conservative (in a "the village is my world" way), either due to tradition or to the number of monsters on the roads (but wait, how do the roads exist in the first place?), and the specificity of your character is that you do stroll beyond these boundaries. The Fallout games actually made this pretty explicit, with you playing a wanderer that the vault inhabitants barely comprehend. In a way, you end up playing Brin/Costner's "the Postman". You're the one nomad moving around, doing the fetch quests for all the radical sedentaries.
And when those start moving around aswell, then it's Soldak mayhem (Din's Curse, Depths of Peril, etc). Beware.
Which is weird, because, especially in oblivion, it was common to see NPCs making special trips twice a year to visit a brother or something. I think the fear of dragons had something to do with why they didn't in skyrim.
Though, another interesting point is: why do so many games with localised villages pay the same price for, say, steel armor? You'd think if no one travels other than merchants, a mining town would sell and buy the armor for much, much cheaper than the town that only has fields and livestock.