Making 3D games requires a deeper understanding of 3D math, at least to do it right, which can be a barrier for a lot of people.
On 2D games, it’s possible to figure out for yourself what’s happening on the screen and do custom solution to problems. When you start involving 4x4 matrices, different spaces, and shaders, it immediately becomes overwhelming, at least to someone who is not familiar with those concepts.
I saw a 4d game here :-)
But I believe the question in general is more in this direction: most devs use an engine and there are 3d engines to use, for those who do not have deeper understanding. Or rather, most do not even have a 2d understanding of their game math. So if they use an engine anyways, why not use one of them 3d ones.
I mean, there even is this rpg paper maker, that is in 3d, even though it is still pixel art.
Maybe there is an anomaly/bias in itch users, and the amateur 3d game makers are just elsewhere. Like making mods for Minetest or Skyrim.
