You’ve obviously never used an optimus laptop. A technology that nvidia refused to support in Linux, and third party hacks had to be developed to make these laptop usable (ie bumblebee).
Then their is their push for crappy EGLStreams instead of GBM for wayland, which they have only now reverted in their 490 driver. After how many years? Time will tell how much theyhave half 
ed their GBM implementation.
AMD in Linux just works. Open source drivers incorporated into the kernel. There are sometimes regressions, but Arch users are the first to test new kernels so that can be expected.
For the longest time optimus laptops were hard to install for regular users. I remember the first time I configured bumblebee and tried to get it working. Nightmare. All because nvidia didn’t support optimus on Linux. At all.
These third party hacks oftern broke too with driver updates and relegation to lts drivers. The 340 driver only works with much older kernels.
AMD just works.