What -and where - are the african and asian and american equivalents in the world of FFXVI? If you look at Valisthea's world map, it's isolated by sea. There are no land channels to "fantasy African" and "fantasy Asia". We don't even know if such continents exist or not, and if they do, we don't know where they are geolocated, although it's been explicitly stated that there does exist more landmass other than Valisthea in FFXVI's world.
https://www.eurogamer.net/naoki-yoshida-addresses-final-fantasy-16s-lack-of-diversity
FFXVI is not only based on Europe - it's based on an isolated version of Europe. It's an "what if an European-like continent were to be surrounded by sea?" scenario, combined with fantasy elements. Therefore, using real-world trading trends make no sense in a fictional world where, for several known and unknown reasons, those trading trends cannot exist. So, outside of magical and other fictional elements, Valisthea IS INDEED heavily based on medieval Europe, but only within the creative bounds that they have intentionally restricted themselves to.
Yoshida is perfectly right here, and I get the impression that people trying to prove him wrong are grasping at straws, hellbent on a mission to try to discredit him for not adding in
racial diversity black people in this particular game.