Agree 100% and I spend a fair amount of time wondering why this hasn't happened. I built piet-gpu-hal because I couldn't find any abstraction layer over compute shaders that supports precompiled shaders. A motivated person absolutely could write shaders to do all the operations needed by Stable Diffusion, and ship a binary in the megabyte range (obviously not counting the models themselves). That would support Metal, Vulkan, and D3D12. The only thing holding this back is a will to build it.