In the past fifty years, fantasy’s greatest sin might be its creation of a bland, invariant, faux-Medieval European backdrop. The problem isn’t that every fantasy novel is set in the same place: pick a given book, and it probably deviates somehow. The problem is that the texture of this place gets everywhere.
What’s texture, specifically? Exactly what Elliot says: material culture. Social space. The textiles people use, the jobs they perform, the crops they harvest, the seasons they expect, even the way they construct their names. Fantasy writing doesn’t usually care much about these details, because it doesn’t usually care much about the little people – laborers, full-time mothers, sharecroppers, so on. (The last two books of Earthsea represent LeGuin’s remarkable attack on this tendency in her own writing.) So the fantasy writer defaults – fills in the tough details with the easiest available solution, and moves back to the world-saving, vengeance-seeking, intrigue-knotting narrative. Availability heuristics kick in, and we get another world of feudal serfs hunting deer and eating grains, of Western name constructions and Western social assumptions. (Husband and wife is not the universal historical norm for family structure, for instance.)
Defaulting is the root of a great many evils. Defaulting happens when we don’t think too much about something we write – a character description, a gender dynamic, a textile on display, the weave of the rug. Absent much thought, automaticity, the brain’s subsconscious autopilot, invokes the easiest available prototype – in the case of a gender dynamic, dad will read the paper, and mom will cut the protagonist’s hair. Or, in the case of worldbuilding, we default to the bland fantasy backdrop we know, and thereby reinforce it. It’s not done out of malice, but it’s still done.
The only way to fight this is by thinking about the little stuff. So: I was quite wrong. You do need to worldbuild pretty hard. Worldbuild against the grain, and worldbuild to challenge. Think about the little stuff. You don’t need to position every rain shadow and align every tectonic plate before you start your short story. But you do need to build a base of historical information that disrupts and overturns your implicit assumptions about how societies ‘ordinarily’ work, what they ‘ordinarily’ eat, who they ‘ordinarily’ sleep with. Remember that your slice of life experience is deeply atypical and selective, filtered through a particular culture with particular norms. If you stick to your easy automatic tendencies, you’ll produce sexist, racist writing – because our culture still has sexist, racist tendencies, tendencies we internalize, tendencies we can now even measure and quantify in a laboratory. And you’ll produce narrow writing, writing that generalizes a particular historical moment, its flavors and tongues, to a fantasy world that should be much broader and more varied. Don’t assume that the world you see around you, its structures and systems, is inevitable.