And yet, people's concept of the "period norm" is way off the mark. Take a look at Kate Elliott's essay that I linked to earlier. And there's not only the faulty gender assumptions, but faulty assumptions that "accurate fantasy" means all white people. If you want to be historically accurate, you'd include POC at all levels of society.
This is very true. It's rare for a fantasy novel meant to be medieval to actually present a world that isn't full of anachronisms. And anyway, the "middle ages" weren't a static, homogeneous time, an social conventions and technology varied at different times and places in Medieval Europe. People often have weird ideas about what things were like in the real middle ages. Many of the trappings of "classic" fairy tale fantasy--castles with fireplaces, taverns, potatoes, turkey legs, half timbered houses, houses with hallways, corsets, elegant carriages, spyglasses etc. actually came to Europe later, more in the early modern era. However, gunpowder weapons did show up in Europe before the early modern era, and those are almost always missing in "medieval" fantasy that otherwise resembles the very late middle ages or Renaissance.
There's also an assumption that every pre-industrial fantasy is meant to be medieval. I ran into issues with that with my first novel, which was actually set in a world that was meant to be around 1600s to early 1700s in terms of tech and to have a culture that wasn't drawn from Christianity and other things that shaped Europe during middle ages and beyond. People kept telling me they "didn't have X, Y, or Z" in the middle ages, or people wouldn't do such and such. The very hints I dropped to illustrate what the tech level was (clock towers, early microscopes and telescopes, flintlock style firearms) were often fingered by critting partners as being anachronistic "for the middle ages."
So many people think fantasy=medieval. Still, agents say they want stories not set in worlds that are based on medieval Europe, and more and more exist and are popular. Some of the fun of fantasy is to play with things and attempt to speculate how a society might develop if it had A instead of B.