I think one of the big problems is that the mods are just as 'addicted' to reddit as the users are. The mods don't want to lose their community. If it's not for all the work that went into it and the joy they get out of it or for providing a community for a niche group, it's for the 'powertrip' of being a mod.
So it's also a case of selfdiscipline. Are they able to restrict themselves.