Look mates, you can argue all you want about 'it's a fictional world, it follows its own rules' but we all see these worlds are Middle-Ages-coded, which is what we base a lot of our assumptions on. The stories don't tell us all the details, because we know what it roughly is like. Yet at the same time, a lot of these stories repeat tropes about the Middle Ages that are actually untrue. Stories pretending crop rotation didn't happen at all, or that people kept getting married before puberty, are just throwing disproven stereotypes around.