what big change could bring down the watchtower?
Can't ban shunning as such, but should at least withdraw charitable status from organisations whose policies promote shunning. Watchtower would clearly fall foul of this as they promote shunning in videos, Watchtowers, organisation books, elders books, elders letters, meeting outlines and more. They could either change their written policies or face sanction. They might attempt to change their written policies while keeping the practice, but that would very difficult to carry out and they would no doubt get caught.
It depends on what you mean by being brought down. I can see splinter groups meeting in private homes discussing and believing WT doctrine for decades after the WT organization collapses (if it does). If you mean, ceasing to exist in the form and size they are now, nothing short of dropping all their unique teachings ala WCOG (which by the way is STILL around under a different name) would do it to the extent that they disappear. I doubt that would do it either. Will they get smaller as the years go by? Yes, I think the evidence points to them hitting their high water mark. But, I just don't see them disappearing. Look at the number of fringe religious groups out there. Now with the internet, you can hold virtual meetings that connect small groups from across the globe.
Tithing - I agree with Morph. It would be a shock at first and fringe folks like me could use it as a reason to leave. But they don't care about those people anyway. If you can convince parents to cut off their own kids, you can certainly convince people to give you money.
Shunning - dropping that would definitely impact the numbers as faders/fringe JWs could walk away without repercussions although many hard core JWs would still shun them. It's simply too ingrained in the culture. It would take an entire generation or two for the shunning to stop.
Doctrine - LOL - They make changes all the time with little to no impact. Most JWs don't even know their latest teachings.
When 1914 has to change.
The answer to the question is found in other failed religions.
Why did the shakers die off? They didn't encourage sex with one's mate. Separate quarters for husbands and wives. They depended on orphans....... when the law changed re orphans being adopted by religions....... they died off.
Christian Scientist......... untreated illnesses and no common sense.Medicine improved they didn't.
Scientology...... total abusive shit heads, fake science. Shunning.
The Amish....limited marriage options and still living in the 17th Century. No outsiders joining up .
Jehovah's Witnesses? No longer relevant. Because of the flow of information on the internet. Bad name for a religion. Bad social skills. Not enough education. The crazy GB and crazy Elders. Their dogma is tacky. They no longer have a message.
Either a federal investigation into their extortion tactics of rank and file congregations / or misuse of billions of $$$$ of funds might bring them down. A federal investigation of child abuse crimes / getting access ( finally ) to the database file which holds 23,000 names of JW pedophiles - then exposing that the WT Society appointed thousands high ranking JW men into positions of power all the while knowing those names were among the 23,000 on the database file list. That would prove intent and knowing collusion.
Or, as some have stated the " no blood transfusion " JW deaths, especially of minor children might wake up the government to investigate abuses of JW members within the cult with thousands of them dying from refusing blood transfusions. I'm thinking it may be any of those 3 things that might eventually bring WT Society down :
1. WT Society extortion of people financially
2. Aiding and abetting church leaders willfully hiding child molesters
3. Forcing, coercing , or pressuring members to refuse blood transfusions resulting in thousands of needless deaths.
Any of these 3 things or perhaps a combination of them may really hasten WT Society's demise
Any of those items would work for me, Flipper & Giordano.
If there were a criminal investigation......
It would have to be something that even politicians, FBI & almost more could not ignore.