When I say "hardware graphics market" I'm referring to high performance graphics workstations, not gaming. There is a whole multibillion dollar market there (probably much smaller than games, but still quite significant). It's unclear what carmack's influence on the high performance graphics workstation environment is, because mini-GL left out all the details that mattered to high performance graphics (line rendering would be a good example).
In my opinion, Mesa played a more significant role because it first allowed people to port OpenGL software to run on software-only cheap systems running Linux, and later provided the framework for full OpenGL implementations coupled with hardware acceleration.
Of course, I still greatly enjoyed running Quake on Windows on my 3dfx card with OpenGL.
Well, put that way it is a market that runs on Windows with OpenGL/DirectX nowadays, or if using GNU/Linux, it is mostly with NVIDIA's proprietary drivers, specially when considering VFX reference platform.
In my opinion, Mesa played a more significant role because it first allowed people to port OpenGL software to run on software-only cheap systems running Linux, and later provided the framework for full OpenGL implementations coupled with hardware acceleration.
Of course, I still greatly enjoyed running Quake on Windows on my 3dfx card with OpenGL.