It shouldn't be, networking should always be in the background and for console games there's no reason why clients should move to another zone - loadbalancers direct new clients to available servers, they don't or shouldn't move existing clients to other servers to make room for new clients.
Chances are they're not doing anywhere near the same thing with modern consoles; maybe in off-the-shelf engine code to get maximum FPS, but the games themselves, not likely. Also because modern video games are millions of lines of code - you don't want to duplicate those tenfold by squeezing every bit of performance out of it. Maybe only in the most frequently accessed codepaths.
Chances are they're not doing anywhere near the same thing with modern consoles; maybe in off-the-shelf engine code to get maximum FPS, but the games themselves, not likely. Also because modern video games are millions of lines of code - you don't want to duplicate those tenfold by squeezing every bit of performance out of it. Maybe only in the most frequently accessed codepaths.