Anticheat became a necessity because too many games decided to remove the ability for players to host their own servers. This sucks a lot when people get some games that have SP/MP but never really bother with the MP part

There’s also the problem that most anticheat software will only stop the laziest cheaters, usually the ones that aren’t willing to pay for the cheating software. There are a bunch of cheat-focused forums and creating the software can be profitable.