This doesn't work with all types of games obviously, and perhaps all online games from here on out will have kernel-level protection. In the meantime, I think we will keep running UT2004 in compatibility mode (or in my case, Wine).
I can play the UT2003 native version for linux just fine (doesn't seem to play nice with amdgpu, but the intel driver seems to be fine).
Regardless, it'll still run on modern systems if you acquire old libc binaries[1] (and preload them), use SDL 1.2 (possibly a patched version[2] which enables Alt+Tab) and start the game using aoss[3] for sound.
[1] https://www.unix-ag.uni-kl.de/~deusser/UT2004/
People should be playing online with others they personally know and trust.
- The percentage of people who want to cheat is not that high.
- Any cheat that spreads widely enough can be obtained by the developers and detected. Cheat developers can and do sell exclusive cheats to smaller groups of people, but fewer people using the cheat also means less disruption.
- With tactics like delayed ban waves, game developers can make cheating risky enough to create an effective deterrence, even if they don't actually catch all cheats.
- If all else fails, game developers can have players manually review other players' replays for cheating, like with Overwatch for CS:GO (not to be confused with Overwatch the game). So obvious cheating will be caught, and if people make their cheating non-obvious, well, that also makes it less likely to annoy other players.
These measures can't stop all cheating, but they don't have to; they just have to deter it enough that it doesn't unduly hamper most players' experiences. In practice, it seems like most games are able to accomplish this.
That said, the existence of cheaters is one of the big reasons why I don't play such games -- and that games include anticheating software is another one of the big reasons, equal to the existence of cheating in terms of how objectionable I find it.
From my point of view, this situation is nothing but a massive train wreck.