Linux

The alternative is to create a solution that checks to ensure players aren't doing something that they aren't supposed to do. Sometimes this is easy, like ensuring they don't move too far in a single server tick, or their velocity doesn't get higher or change faster than it should be. Sometimes this is more difficult, like not transmitting the location of enemy players unless they're actually visible to that player. No matter what, it's custom.

Other AC solutions are mostly plug-and-play. They still require some effort, but not nearly the same amount. It's much more appealing to a studio to spend time on developing the actual game, and pay for an AC solution, than to hire people to just handle AC.

There's one more example, that's even more expensive, of using AI detection, which I think Valve still does a lot of. They've been adding this for much longer than the current AI movement has been happening. It takes a lot of data and tagging that data for cheating or not. It's not a perfect solution (Valve does other solutions in addition to this), but it can work really well.