People play on DS because they choose to. No one is forcing you to stay here and they sure as hell aren't going to force you to leave. The community here is pretty unique.
People who leave DS always come back.
I think that used to be true, but things are a little more far gone than I've seen in my tenure. When I logged on Demon Soul a few times, the only people I still recognized were all in Reminence; Everyone else was a stranger.
I think people (including myself) kept coming back because of the community, good or bad (We all know I've had my share of experiences) but from what I can tell the majority of folks I knew, who made Demon Soul what it was, are gone. I mean, it was pretty far gone and then within a few months Rare, BAD, and Arete (Horde LTD) folks all left.
IMHO =-) At the same time, here I am on DS forums.