At this point, it's up to the user to make that trade-off, but most of the players don't have enough information to make that decision.

Sure, I wouldn't want any cheaters on my games, but these systems are not fool-proof and cannot circumvent every single cheater out there.

Dedicated enough cheaters are getting what they want anyway, while the unknowing user is left with a backdoor on their systems (in the event of a compromise)

The goal isn’t to stop every cheater, the goal is to reduce the number of cheaters. They achieve this by making the monetary cost of cheating so high that it doesn’t happen often enough to affect the vast majority of players. “Private cheats” are expensive, “public cheats” get killed off quickly, pushing up the cost of “private cheats”.

It's already useless (for motivated attackers), since you can capture video output and send input from a separate device

Complexity increases shitton of times

If you reduce amount of cheaters from 1000 to 10, then it's still huge win for the player base and average player's experience

None of this was as big a problem twenty years ago, despite cheats being easier to make. We had community run servers with occasional admin presence. All you need is an IP and username based banlist. I don't care if occasionally an admin is a power hungry 12 year old, I can just go next door.