Who exactly is "Linux"? What entity, specifically, would work on kernel anti-cheat? The only realistic company who would care about this is Valve. So really you should say Valve, not Linux.

That's the biggest problem with Linux on the desktop: outside of Red Hat and Canonical (neither of whose business has anything to do with gaming), there is basically no well-funded company that cares about it at all. Linux already works great for the use cases that matter to the people who develop Linux, who mostly are not trying to compete with Microsoft or Apple.