It’s probably because white Americans are the majority of the market in the US and tend to be uninterested in characters of a different race, whereas POC have had little choice since birth but to empathize with a whole cast of characters that do not look like them.

I am thoroughly unconvinced by arguments that “Meh it’s medieval Europe” when these fantasy races have purple and green skin.

It’s not because “write what you know” since most authors probably know SOME poc. And again- the races/beings in fantasy are made up. For sci-fi and dystopia, it’s speculative fiction, so there are very little rules.

Let us be honest. It’s a lack of interest, both by consumers and authors.