Oh, and there are other graphics makers that could theoretically work on linux, like Imagination’s PowerVR, and some Chinese startups.

The problem is making a desktop-sized GPU has a massive capital cost (over $1,000,000,000 just to ‘tape out’ a single chip, much less a line), and AMD/Nvidia are just so far ahead in terms of architecture. It’s basically uneconomical to catch up without a massive geopolitical motivation like there is in China.