There might be a subset of people, such as yourself, that looks for CUDA as a hard requirements when buying a GPU. But I think it's fair to say that Vulkan/Spir-V has a _lot_ of investment and momentum currently outside of the US AI bubble.
Valve is spending a lot of resources and AFAIK so are all the AI companies in the asian market.
There are plenty of people who wants an open-source alternative that breaks the monopoly that Nvidia has over CUDA.