People grow up and responsibilities appears, i'm pretty sure that people still play toribash because of the long time they have been here (nostalgia and history) and the principal reason of that being friendships made here.
That's why you see the same members active.
Also, i have to admit that i wouldn't be very active if i didn't had friends here, is quite obvious that many people stoped playing because of their friends that don't play anymore (playing other games).
I still miss 2010-2013, for me it was probably the best era of toribash.