Except most anti-cheats started on dedicated servers because it turns out most people are not interested in policing other players.

Punkbuster was developed for Team Fortress Classic, even getting officially added to Quake 3 Arena. BattleEye for Battlefield games. EasyAntiCheat for Counter-Strike. I even remember Starcraft 1 ICCUP 3rd party servers having an anti-cheat they called 'anti-hack'.

You can still see this today with modern dedicated servers in CS2: Face-It and ESEA have additional anti-cheat, not less. Even modded 3rd party server FiveM for GTAV has their own anti-cheat called adhesive.

I would argue a lot of the early anti-cheat was just as much about giving admins and communities better tools to police themselves as it was about automated cheat detection.

Like here's 2006 Punkbuster for Battlefield 2 (BEye might have been made for BF:V but Punkbuster was what I remember being used by servers). [1]

It automatically kicked on cheat detection but it didn't ban. It provided logs for admins to use for bans. It provided a way for admins to give community players the power to kick. It provided a player GUID based on CD key. It provided an online identity verification/registration system (though I don't remember anyone using this). It let admins take screenshots of players' screens.

[1] https://web.archive.org/web/20060515160425/http://www.evenba...