I think there are enough people with psychopathic tendencies at the helm. This did happen in the 1800s with both the Bible Students and the Millerites, however nature abhors a (power) vacuum.
I know quite a few CO/DO would declare the end of the world is nigh and start their own little cult, for areas where that didn't happen one or more of the elders in the congregations would do the same. The religion would simply fracture as it has in the past, some would be more devotional and extreme, while others would not.
You'd get anything from full congregations in one location to a few people getting together once a month on the other end, over the next 100 years you'll basically be back in the place we are now, some will have gotten big, some will have disappeared and some may still refer to their ancient roots as the WTBTS does today with the Bible Students while helpfully forgetting their link to some of their more seedy people and the fact that WTBTS are not the Bible Students, but were created from a disagreement with them.