There is only one timeframe that matters to a Jehovah's Witness: the present.
"So what if we taught that in 1993? This is our present truth!
Jehovah's Witnesses are being conditioned to think that the organization's history is unimportant, "the way Jehovah is blessing the work now proves that this is his organization".
Here's a question: If you were born into a Catholic family in 1922, lived 70 years and died in 1992, what is your current standing before Jehovah according to JW doctrine? You have been released of your sins because the wages of sin is death and you await a resurrection.
Here's another question: If you were born into a Catholic family in 1922, converted to become a Jehovah's Witness in 1952, lived 70 years and died in 1992, what is your current standing before Jehovah according to JW doctrine? You have been released of your sins because the wages of sin is death and you await a resurrection.
That's right! The preaching work carried out from the 1870s into the 20th century was pointless. All those people are now dead and their status is no different to their comtemporaries of the time.
The past is irrelevant. Only the immediate future matters to Jehovah's Witnesses.