Witnesses would simply discard that quote as something that has been replaced by the light getting progressively brighter. They would say they were not wrong. They would say that is how Holy Spirit led the GB to interpret the scriptures then. They would say they it is now clear there is an overlapping generation, that it can only be a single overlap and that the end is imminent.
They might claim that if the overlapping generation had been clear earlier then it would have meant the growth of the organisation would have been different so Jehovah allowed the older understanding to be presented. They will repeat they were not wrong and that what is now taught is not materially different and that context and time means both explanations were/are correct and not contradictory.
They will be less ready with an answer when asked to explain why the older explanation could be explained from the Bible using scripture (albeit their interpretation) yet the new explanation cannot be explained with a single scripture? Why is it that the progressive revealing of meaning has resulted in something with less scriptural basis?