Personally, I don't think they will ever die out. the people who will finally wake up to it will be in it for so long, leaving it will seem insane. And there will be new people, future generations shedding "new light" into bible teachins that will keep it going. And as long as there are people in lower economic backgrounds who are downtrodden and looking for some purpose of life and for people to belong to in a society that values the individual pursuit while ignoring that some people don't have any other pursuit or goat but to survive....
Sorry, long ass run on. I don't think they will die, but like everything else in this world they will change and evolve, possibly even branch off into another group. Die off, Hells nah. Unless one memorial comes and everybody is instructed to pass and take a sip of the new liquid that represents Jesus christ blood... you know some super special red kool-aid... then maybe they will. Maybe...