Did you read the last part? Pytorch uses drivers, and drivers exists for Google's TPU and Apple's M1 GPU as well and both works pretty well. I have tested both and it reaches similar MFU as Nvidia.
I never claimed it was easy. I meant in my opinion it is in the order of 10s of millions dollars of investment, not a trillion dollar CUDA moat that people comment here.
Anyone that wants off the shelf parts at scale is going to turn to Nvidia.