Retraining a large high paid user base is often a non-starter. To put this in perspective, Boeing’s eventual retraining costs for all the pilots for the 737Max was around 5 billion dollars.

Looking at software more specifically the Linux foundation reported based on software dev salaries in 2008 it would be 1.4 billion to only write the Linux kernel.

Up until about 2023 there wasn’t enough money involved to have any reason to make a real CUDA killer even if you could get it adopted.