Life is too short, you have to take into account the other things that effect a religion like the Jehovah's witnesses and the fact that they've gone through one radical upheaval in the past where they made dramatic changes. I'm referring to the Rutherfordian era.
If things were to remain the same in society, then you would have a point. They may see a drastic reduction in numbers like what happened during Rutherford's iron fisted rule but it would still be possible for them to adapt.
I myself don't see the Jehovah's Witnesses disappearing due to social changes that I see forthcoming. Apocalyptic religions like theirs thrive on insecurity and social upheaval. They're only likely to die out when there's social stability for a long time, let's say 2-3 generations in order for the die hards to totally disappear and the religion becomes a faint grandchild's memory.
Believe me, we're stable right now but it won't stay that way for long.
As soon as stuff really starts hitting the fan worldwide, in 10 to 20 years, this religion, even if it has dwindled in numbers, will get a steroid shot which will give it the opportunity to reinvent itself, as it has previously done. Technology would be irrelevant because the Governing Body could make use of it themselves as soon as the will surfaces.
Reality, including social reality, is multi-dimensional and we have to see the whole picture. The Jehovah's Witnesses have done a lot to mess themselves up but so has this country and civilization itself. In the long run all things die out but within our short lifespans tyrannies last.
Still, I hope I'm wrong about the Witnesses, but something just as evil is likely to fill the vacuum.
Oh yes, I left my reasons for believing that society will destabilize unsaid, but that's another story.
Villabolo