A couple of thoughts, but I largely agree with you.
> Obfuscating the game will only go so far, as demonstrated by the mixed success of Denuvo DRM.
Denuvo is for the most part DRM, rather than anticheat. It's goal is to stop people pirating the game during the launch window.
> The game will not be the most privileged process on the machine, while cheaters are glad to allow root/kernel access to cheats.
This ship has sailed. Modern Anticheat platforms are kernel level.
> TPMs cannot be trusted to secure games, as they are exploitable.
Disagree here - for the most part (XIM's being the notable exception) cheating is not a problem on console platforms.
> AI enabled cheats no longer need any internal access at all. They can simply monitor display output and automate user input to automate certain actions like perfect aim and perfect movement.
I don't think these are rampant, or even widespread yet. People joyfully claim that because cheats can be installed in hardware devices that there's no point in cheating, but the reality is the barrier to entry of these hyper advanced cheats _right now_ means that the mitigations that are currently in place are necessary and (somewhat) sufficient.