There are plenty of ways to curb cheating. It still happens in fighting games too, but the way the genre works makes it far less prevalent. FPS games these days are largely designed around things that are hard for humans but easy for computers to do while looking like humans. Just spitballing, but if aiming was less of a concern, like it might be in the likes of old James Bond games or Metroid Prime, there are other ways to build competitive strategy around an FPS besides how well you can get your tiny crosshair to line up over a tiny target. Otherwise though, I'm with you on it being inevitable. There's no way to truly stop it.