I agree with your overall point.

However, as a professional codemonkey, I promise you that root-level AC is in fact less secure than server-side heuristic AC + user reporting, and tends to be user-hostile due to false-flagging of modified systems. Root-level AC can be bypassed rather easily these days with DMA and other out-of-band tooling.

As a case-study, League of Legends lacked any root-level AC for well over a decade, and was arguably the most popular game in the world at points. Cheaters were extraordinarily rare; the average player would typically encounter well under a dozen cheaters per thousand games.

Riot Games then released Valorant with full root-level AC, and had an aimbot explosion within a few months - mostly because they devalued player feedback & reporting in favor of their “robust” automated AC solution. Their overall anticheat strategy became less reliable on the whole, but they stuck to it because root-level AC is cheaper and easier to execute from the corporate-profit POV.