It would take away a huge chunk of their advantage, no doubt about it. Let Nvida compete on merit instead of lock-in. Then you can say their advantage lies in being better. But Nvidia is very lock-in oriented, which undermines the claim that they are so much better than everyone.

CUDA IS the merit. They’ve been developing the software stack to make GPU programming accessible for 2 decades now. They’re a software company as much or more than they are a hardware company. Ignoring this fundamentally misunderstands why they’re in the position they’re in now.

It's not the merit - it's the moat (i.e. lock-in) as the linked article states. Merit in this context would mean something you can compare across different GPUs. For CUDA - you can't. I.e. it's a tool to force you to use Nvidia.