While that might be technically true, the kernel module is only a tiny fraction of the driver stack.

Also, I'm not interested in rewarding a company that spent decades making life difficult for open source users and developers, when there are competitors who have done far better (and have more experience) in this space.

The kernel driver is a rather small piece of the overall puzzle though, itps just the pipe that GPU commands are passed through. The bulk of the GPU driver code (and the majority of its impact on performance) is in the userspace components like the shader compiler and the OpenGL/Vulkan libraries. These are closed source.

The exception to this rule is that the kernel driver is responsible for power management and controls the GPU clocks, but as part of opening up the kernel driver NVIDIA made reclocking available for the fully open driver (nouveau/nvk) to use as well which means the performance differences between the two driver stacks are now down to optimizations.

they are open core not fully open source

nvidia has released opensource kernel level drivers

"Not every GPU is compatible with the open-source GPU kernel modules.

For cutting-edge platforms such as NVIDIA Grace Hopper or NVIDIA Blackwell, you must use the open-source GPU kernel modules. The proprietary drivers are unsupported on these platforms." - developer.nvidia.com

Only 9 years after AMD, and 13 years after Linus said "fuck you Nvidia" during a talk for being such a difficult company to work with.