Also remember that one of those 2 companies has opensource drivers for Linux for their old GPUs, while the other doesn't (newer NVIDIA GPUs have an opensource driver but this isn't the case for the 10xx series). Users of legacy NVIDIA cards needs on Linux needs to use their old driver branches, with results that are less than optimal to say the least.
[1]: https://videocardz.com/newz/nvidia-officially-ends-geforce-g...
[2]: https://arstechnica.com/gadgets/2025/11/amd-says-that-its-no...
A lot of the serious CUDA compute stuff is also not supported on all platforms (it's linux only, because why would you do such stuff on windows).