Well, Bright got burnt out with Staff work and needed a break, Clef is still around, Crow got busy with life, Gears got sick but is now semi-active after recovering, The Administrator got sick and never really became active again, Kondraki got banned and then didn't return after it expired, Mann is still around, the list goes on. Everyone has there own reasons of course. Something you have to remember, most of the these people were here in the beginning as well as before the wiki was around, and the wiki has been around for almost 13 years now. People have kids, furthered their careers, and overall got too busy to hang around. Life happens.