I can only speak for myself, but my understanding is that the Navi cards are not intended nor advertised for compute. Now, one might wish to get a consumer card with Arcturus after the Instinct MI100 is released or dislike that the Radeon VII is discontinued, or even that it wasn't split into render and compute lines, but basically, to me the complaint about Navi not being supported by ROCm sounds a bit like buying a boat and complaining that it can't fly. Driver support was bumpy for me with Linux 5.0 or so, but I haven't had trouble with just running whatever kernel Debian ships for quite a while now. But I must admit I don't use the GPU for anything but compute, so I don't know about graphics.

But your mileage may vary, I don't want to make people swear.

a GPU is a GPU, it's all just programs running on the shaders.

If AMD is unwilling to properly support its consumer GPUs in GPGPU workloads and NVIDIA is, then well... sounds like a good reason not to buy AMD.

It's really not a major ask, people have been running GPGPU programs on consumer cards since forever, even though they're "consumer" and sold as graphics cards and not compute accelerators. NVIDIA basically does this on purpose, people use their personal hardware to get a foot in the door of the ecosystem and end up writing programs that get run on big compute GPUs which NVIDIA makes big profits on, it's very intentional.

If AMD chooses not to do that, well... can't really blame people for avoiding their stuff when NVIDIA is willing to let you do this stuff on their cards and AMD isn't.