How much of a percentage do gaming rigs actually constitute of CPU sales?
Gamers are willing to pay three times the price for hardware just to get a few percent more performance. I would claim that drives innovation.
I imagine professional workstations for industries such as software development, visual arts, industrial design, film production, music production etc. are large users of high end CPUs.
None of them uses overclocked CPUs (like Intel's K-series) that's fairly standard for high-end gaming