In 1974 I went to a special talk at the Inglewood Public Forum (Sothern California) to listen to a talk about 1975 from none other than Frederick Franz. He was then vice-president of the Watchtower.
He specifically said that the end would occur anywhere from a few months to a few years after September of 1975. He specifically excluded the possibility that it would be decades after 1975. Using the logic of the "Adam and Eve gap" he said that if it were to take decades than that would mean that Adam would have been without a mate for that long and that would tempt Adam into bestiality!!!
His statement, in his sing song voice, was: "Would Jehovah let Adam to be tempted into bestiality? Noooo brothers and sisters, Jehovah would not allow that."
So what would happen if Freddie the beast never existed? The JWs would have been a little more dull but, like Outlaw said, they would simply have somebody else upstairs.