John that's interesting!
But the witnesses are so slick with words, i think they'll use their manipulation mastery to twist it in such a way as to keep most of the flock enraptured.
I would think they are losing followers to the 'generation overlap'...dropping 1914 would help with that. Most of the reasonable sort of witness would like to lose any association with any specific date (and therefore false prophecy). But you're right, it would be a huge admission that they were wrong. And unlike the other false date prophesies, it has been written about constantly in their literature. Not easy to shake off. Time will tell what they decide to do. They can't stick with it much longer.