[MindSpunk]

Put briefly:

GPUs don't work like CPUs, at all, and need to massaged carefully to run efficiently. You can't just give a GPU an `int main()` and go ham. The APIs we get to use (DX12, Vulkan, Metal, WGPU) are all designed to abstract several GPU vendor's hardware architectures into an API that's just low-level enough to be efficient without forcing the app to explicitly target each GPU itself. There's no one way to run fast on everything with more than a trivial program.

As for why no 'universal high-level native GPU compute API' exists, GPU vendors don't want them because it's too much effort to implement. They'd much rather everything go through a low-level interface like Vulkan and the high level stuff get done by 'someone else' consuming Vulkan. Each new 'universal' API requires buy-in from 4+ different hardware vendors. Someone needs to painstaking specify the API. Each vendor must implement the API. Those implementations will be broken, just look at Android drivers, and now your 'simple' universal API is actually 4 different APIs that look almost the same except for strange esoteric behavior that appears on some hardware that is completely undocumented.

This is what OpenGL was and is why Vulkan, DX12 and Metal exist. The universal 'simple' API doesn't exist because it's too hard to make and not useful enough for the people programming GPUs regularly.