At the end of the day it worked for them not because of Society but because the priests pushed the individual members of the congregation into compliancy. It's what the Confessional is about. The heirarch is never wrong. Even when he or she is.
Let's remove it from a religious setting and look at a secular equivalent, Haut de la Garenne in Jersey. There too the civil authorities have been shown to be covering up a scandal, in forcing the equivalent historian-journalist Leah McGrath Goodman out of the country, which was sufficient to cause a rebound and full judicial investigation. See the difference? Cover-up and little action in the one case, cover-up and judicial investigation in the other, which will likely lead to criminal charges. It's too early to preempt the outcome, of course, but the basic facts about Jersey are clear from the survivors. The basic facts about Tuam could also be clear - if the survivors were given the confidence to speak for themselves.