As my Granddad used to say - 'if things don't change they'll stay as they are'. Basically I think religion will go it's merry way polluting humankind for centuries yet.
However, hypothetically...
What if Islamic exremists get hold of nuclear weapons, and use them against Christian extremists (mainly in the U.S.)? The resulting scenario, of millions of deaths and the potential for the extinction of the human race, would mean the survivors would almost certainly ban overt religious practices as a matter of fear of it happening again.
So, I think it won't just 'happen' like the JWs think but it could happen following an extremely violent and bleak moment in human history.
In which case most of us won't be here to say anything to Jehovah's Witnesses anyway.