Also, while AMD's OpenCL implementation has more features on paper, the runtime is frequently broken where NVIDIA's claimed features actually all work. Everything I've heard from people who've used it is that they ended up with so much vendor-specific code to patch around AMD's bugs and deficiencies that they might as well have just written CUDA in the first place.

This is an old article but the old "vendor B" stuff still rings incredibly true with at least AMD's OpenCL stack as well.

https://richg42.blogspot.com/2014/05/the-truth-on-opengl-dri...

Thus NVIDIA actually has even less of a lock-in than people think. If you want to write a better OneAPI ecosystem and run it on OpenCL runtime... go hog wild! NVIDIA is best at that too! You just don't get the benefit of NVIDIA's engineers writing libraries for you, all that obviously takes place in CUDA.