That's ignoring that many of the buildings we *do* see in Skyrim are very old. The Blue Palace in Solitude, Dragonreach and Jorrvasskr in Whiterun, the Palace of the Kings in Windhelm, and the entirety of Markarth, for instance--there's no reason for those buildings to be affected by any trade or war issues in the last 200 years. It therefore seems odd that the biggest and most ostentatious building in the entire game belongs to a vampire and his cult!