One we can play AAA games I am literally ditching windows forever. Steamos is the best thing that has happened to gaming
We already have the technology now to do it better. A combination of only sending what info a client should have, and server-side checks. As soon as something like UT ships with that built in we can hopefully forget about this horrible hack we currently have to check for cheats.
The goal of anti-cheat isn't to stop the world's most advanced cheaters. Those are already unstoppable because they now use Direct Memory Access over the PCI-E bus, so the cheats don't even run on the same computer anymore. However since those cheaters are few and far in-between they can be handled through player reports.
The goal is to stop the mediocre cheater who simply downloaded a known cheat from a cheating forum. If you don't stop those you'll get such a large wave of cheaters that you can't keep up with banning them quickly enough.
I imagine that most game devs just look at the incredible amount of work this takes to implement and complexity it adds, and decide to not bother. Valorant can do it because the game itself is low complexity, the developer has deep pockets, and also the added competitive integrity is valuable.
As far as I see the only way around not sharing anything that's outside of the immediate perception of a player is to have the audio and graphics be entirely rendered server-side.
It's infeasible for the server to keep track of each player and do frustum and raycasting to every other player to check who can see who every frame.
Culling out of view entities also has the problematic effect of when a player spins around you now have to stream in several big chunks of world state in the few milliseconds before the user clicks to get that 180 no-scope.