I honestly think that the FBI is breathing down the admins' necks. Being as this place used to be the place to go for zoo porn and underage girls masturbating on stickam (r.i.p. in peace ;_;), I'm pretty sure that they've been threatened more than once about being taken to a federal court over this. And the FBI intruding on this place isn't anything new; many undercover agents browse these very boards to find pedophiles and arrest them (and yes, there have been investigations involving motherless users posting and trading illegal content here). This place died the second it grew popular, and no one is brave enough to start a new site (doubt it would even get popular anyway).
tl:dr the feds killed this place. Don't blame the admins because they were pressured and most likely threatened to delete content. It's a miracle this place is still around today considering the shit that's been posted here.