For accelerated rendering etc cuda is the standard, and because of it Nvidia. And it's like that for a lot of other niche areas. Accelerated encoding? NVIDIA, and CUDA again. Yes, AMD and Intel can generally do all that these days as well. But that's a much more recent thing. If all you want to do is game, sure that's not a big issue.

But if you want to do anything more than gaming. Say video editing and rendering timelines. Nvidia had been the standard with a lot of inertia. To give an example of how badly AMD missed the boat. I have been using accelerated rendering on my gt 750 in blender for a decade now. The card came out early 2014. The first AMD card capable of that came out one month before the end of 2020. Nearly a 7 year difference! I'm looking at a recent Intel arc or battle mage card or a 6xxx series AMD ATM. Because I run BSD/Linux and Nvidia has traditionally been a necessary PITA. But with both of them now supporting my workflows. Nvidia is much less necessary. Others will eventually leave too. As long as AMD and Intel don't fuck it up for themselves.