I wrote a snarky response because of the final insulting comment in yours but then thought better of it, going to try to address a couple of your points legitimately even after the unnecessary personal attack.
It's a lot cheaper to make your server dumb. It costs you less in programmers with deep multiplayer programming experience, it costs you less in ongoing hosting because of reduced CPU usage, and it makes the problem less "yours" as a developer.
I'm saying that's shitty that the developers will try to save money that way rather than investing in actual effective, privacy-respecting cheat prevention.
Your argument seems to be that a quake-style predictive algorithm is the only solution possible for online games. I doubt that is the case, but even if it were, using some raycasts on the server for some basic sanity checks on what data to send to players is an example of where lots of developers just can't be bothered.
If you want to dismiss machine learning as heuristics, I'm sorta ok with that, as I think they are just glorified heuristics, but even the most basic analysis isn't done by most developers. Instead, they rely on the sales pitches of various anti-cheat software and don't implement anything beyond it, even when there might be some low hanging fruit.
I am not saying developers are lazy, there's tons of stuff to work on. I am mad that this problem gets repeatedly pushed onto the users rather than the developers, though, and I think it's reasonable for me to offer some pushback when both my CPU cycles and my privacy are being abused.
QuantumCommuter