I always like the think that once you've played for a certain time, you can never really completely quit GunZ. A lot of old players come back after a long time, they just need something to keep them there. You should swing by after the patch and indulge in a little bit of nostalgia.
This really, there's a reason why there are so many of the ones left playing that came from I-Gunz or early Ijji era (Except for having an functional social infrastructure to stick new players).
Many enjoy playing for the sake of the reward the gameplay itself give rather than the egostroking rewards there might otherwise be.
I myself will never really quit before i either reach what i would feel would be the ceiling of my capabilities or there's not a single soul left to play against.
Which i doubt will happen since there's still so many dropping by now and again for their fix for their addiction, which, is always ever oh so present.
Also i'd like to think there's a string of hope thanks to the game actually being good (and also i guess thanks to filling a very, very small niche), just takes people getting out of the slump.