Once you can execute arbitrary code it's easy to figure out. The point is that it makes it harder to get a vulnerability to the point where it executes arbitrary code in the first place.
We're talking about different security models. Whereas anti-cheat companies seek to prevent code execution or introspection in a certain context (the game) by a user that already has full privileges over the machine, other mitigations seek to prevent privilege escalation or initial access. For example (simplification), a remote exploit that relies on a specific address to work would now have to find an additional information leak. Similarly, code running in usermode cannot simply* know the addresses of objects in the kernel.
* In practice this isn't really true, and there are many ways to bypass KASLR
[1] https://en.wikipedia.org/wiki/Defense_in_depth_(computing)