I don't think the current rate of people quiting
is higher than before, there were always players
and admins quitting, just because you can't play
a game 24/7 several years (ok some people can :-)
Even when playing the best games ever I always
needed to take a break after some time, it's
better to relax some days then play it again
(otherwise it is impossible to not get mad,
e.g. in Goldeneye I played a very hard level
and was killed in 2 seconds after 20 minutes of
playing it and finally coming to the last tunnel...
but after some weeks I have beat it, and this before
my brother got it
)