I was sitting down with a friend of mine who was a professional 3D modeler. By observing him working with Blender on my Blackbird workstation for a simple modeling job of a snow man, I realize the biggest blocker that push Blender to the finish line is the lacking of GPU acceleration rendering, specifically the Blender Cycles engine.
As you might have known that AMD ROCm is huge and complex so I rule out any possibility of AMD ever support PPC64. Other engines like CUDA is out of question because NVIDIA does not even offer driver for PPC64. The same goes with Intel unfortunately. The only option is OpenCL which is vendor-neutral but sadly its non-CUDA closeness design and buggy implementation forced Blender team to drop OpenCL few years ago.
What are options out there? LuxCoreRender is one potential solution because it supports OpenCL. In theory we could achieve it like this: LuxCoreRender → OpenCL API → RustiCL (Mesa) → radeonsi (Gallium) → amdgpu (kernel) → AMD GPU. I am unsure how reliable RustiCL is so this approach might be not working at all. However let's assume that it may work, there is still a huge effort to get LuxCore running on PPC64.
I am wondering if any community member has attempted to tackle this blocker issue before.