Also the stability of the Kingdoms of Westeros is ridiculous given their ages. Supposedly they were divided into the Kingdoms of the North/Vale/Iron Islands/Reach/Rock/Stormlands/Dorne in the Age of Heroes - 10,000 years before the Targaryen conquest. 10,000 years is twice as long as all of recorded human history. In that time on earth, dozens of empires have risen and fallen. The center of civilization moved from the Middle East to Egypt to Greece to Rome to Byzantium & Arabia to western Europe to Britain to North America. Independent civilizations with equal claims to greatness sprung up elsewhere on the globe. Civilizations got conquered, technology advanced, genocides and plagues and famines happened, languages changed, and dynasties typically lasted a couple hundred years, if that.

Meanwhile, over in Westeros, the same 7 kingdoms have been ruled over the same geographic extent by the same 7 families at roughly the same level of technological development for 10,000 years. It took outsiders with dragons to conquer them. No explanation is given over how you could maintain what appear to be feudal structures over a 3000+ mile continent with bronze age technology.