What's wrong with CUDA? I avoided it for years because it's proprietory but about one year ago I started using it because all the alternatives (OpenGL/Vulkan compute, OpenCL, WebGPU, ...) couldn't quite do what I wanted, and it turned out to be a game changer. Nothing comes close to it. Now I'm hooked because there simply isn't an alternative that's as easy to use, yet powerfull and fast.
I wish there was an open alternative, but NVIDIA did several things right that others, especially Khronos, do not: The UX is top-notch. It makes the common cases easy yet still fast, and from there you can optimize to your hearts content. Khronos, however, usually completely over-engineers things and makes the common case hard and cumbersome with massive entry barriers.
Those are some poor arguments, imho, because there literally is no other option than CUDA. The alternatives are so bad, it's far better to be vendor-locked and being able to get stuff done, than not being able to get stuff done at all.
As I said, I avoided it for years because of the reasons you mentioned. Turns out I could not avoid it any longer because it's the only (meaningful) option that could do what I needed, has serious support, and great UX. And NVIDIA is hardly to blame because they simply made sure to build a good product. It can't stop AMD, Intel or Khronos from creating a competitive alternative, but so far they haven't.
And regarding support, so far NVIDIA has shown excellent continuous support for CUDA, whereas OpenCL and OpenGL are the ones that went down. And I've chosen CUDA over rocm precisely due to support reasons, because AMD has always treated it as some kind of side gig with uncertain future.
I really wish they would, and properly, as in: fully open solution to match CUDA.
CUDA is a cancer on the industry.