Nobody has mentioned this, but https://docs.scale-lang.com/ is doing some amazing work on this front. Take CUDA code, compile it and output a binary that runs on AMD. Michael and his team working on this are brilliant engineers.
However the amount of resources at stake is incredible. The delta between NVIDIA's value and AMD's is bigger than the annual GDP of Spain. Even if they needed to hire a few thousand engineers at a few million in comp each, it'd still be a good investment.