When you're #1, you can go all-in on your own proprietary stack, knowing that network effects will drive your market share higher and higher for you for free.
When you're #2, you need to follow de-facto standards and work on creating and following truly open ones, and try to compete on actual value, rather than rent-seeking. AMD of all companies should know this.
I don't know about that. You could kinda argue the opposite. "We improved CUDA. Oh it stopped working for you on AMD hardware? Too bad. Buy Nvidia next time"
Are we talking about the same NVIDIA? The entire Nvidia GPU strategy for nvidia is - make a feature (or find existing one) that performs better on their cards - pay developers to use (and sometimes misuse) it extensively.