X11 has a "standard compositor interface", but X11 compositors generally don't talk to the hardware directly, they talk to standard X11 drawing APIs like OpenGL

X11 has a "standard compositor interface", but X11 compositors generally don't talk to the hardware directly, they talk to standard X11 drawing APIs like OpenGL or XRender. What you're talking about is really "Xorg drivers", a legacy from the time when Xorg was responsible for display hardware, and the OS kernel was responsible for every other kind of hardware. Hardware definitely needs drivers, but these days the Linux community has settled on the model that all drivers should live in the Linux kernel, where they can share common code like "talking to the PCI bus" and security infrastructure. What you're proposing is that, instead of having one driver layer from "standard API" to "hardware interface", there should be multiple redundant driver layers, so that NVIDIA can implement whichever layer optimally balances their desire to support customers with their desire to hide their intellectual property. That's not a crazy position (NVIDIA certainly holds it, and they're no small fry!) but telling Libre graphics-stack people "you need to make your architecture more complex and do extra work for free, to make this multi-billion-dollar company feel more comfortable" is always going to be a difficult proposition.