My only guess is they have a parallel skunkworks working on the same thing, but in a way that they can keep it closed-source - that this was a hedge they think they no longer need, and they are missing the forest for the trees on the benefits of cross-pollination and open source ethos to their business.
Meanwhile CUDA supports anything with Nvidia stamped on it before it's even released. They'll even go as far as doing things like adding support for new GPUs/compute families to older CUDA versions (see Hopper/Ada and CUDA 11.8).
You can go out and buy any Nvidia GPU the day of release, take it home, plug it in, and everything just works. This is what people expect.
AMD seems to have no clue that this level of usability is what it will take to actually compete with Nvidia and it's a real shame - their hardware is great.
It's annoying as hell to you and me that they are not catering to the market of people who want to run stuff on their gaming cards.
But it's not clear it's bad strategy to focus on executing in the high-end first. They have been very successful landing MI300s in the HPC space...
Edit: I just looked it up: 25% of the GPU Compute in the current Top500 Supercomputers is AMD
https://www.top500.org/statistics/list/
Even though the list has plenty of V100 and A100s which came out (much) earlier. Don't have the data at hand, but I wouldn't be surprised if AMD got more of the Top500 new installations than nVidia in the last two years.