I see where you are coming from, but actually, from their point of view, they HAVE said that. Just because it is not coherent, does not mean the Society view it as "unsaid"!
In the Revelation book, it is constantly stated that (in more or less words) the fulfillment of "Bible prophecy" upon JW's "proves" they are God's people.
The Societys' position is fairly clear. They claim that in 1918, as per Malachi 3, Jesus came to inspect the people claiming to be his, which included all Christendom. He found JW's were the closest to the "truth" (which would be obvious if he had been using them since 1874.) For a period he refined them, which was done thru the imprisonment of the board of directors. Then in 1919, Jesus fulfilled a "remarkable" prophecy toward the JW's by "resurrecting them to heaven" figuratively, by freeing the board and reinvigorating the preaching work. This whole series of events is the "proof" the Society points to.
I understand what you are saying, but I know I was told that at Bethel, and all the brothers and sisters I ever hung around with understood this to be the case - the events of 1914-1919 were the "seal of approval". I am sure this is mentioned somewhere in the Revelation book.
*** re chap. 6 p. 32 Unlocking a Sacred Secret ***
Early in 1918 the Kingdom activity of Jehovah’s people met with great opposition. It was a time of testing earth wide, and fearful ones were sifted out. In May 1918 Christendom’s clergy instigated the imprisonment of officials of the Watch Tower Society, but nine months later these were released. Later, the false charges against them were dropped. From 1919 the organization of God’s people, tried and refined, moved zealously forward to proclaim Jehovah’s Kingdom by Christ Jesus as the hope for mankind.—Malachi 3:1-3.
As Jesus began his inspection in 1918, the clergy of Christendom no doubt received an adverse judgment. Not only had they raised up persecution against God’s people but they had also incurred heavy bloodguilt by supporting the contending nations during the first world war. (Revelation 18:21, 24) Those clergymen then placed their hope in the man-made League of Nations. Along with the entire world empire of false religion, Christendom had fallen completely from God’s favor by 1919.
*** re chap. 25 pp. 169-170 Reviving the Two Witnesses ***
23 The public press joined the clergy in vilifying God’s people, one paper saying: “The finis of The Finished Mystery has been given.” Nothing, though, could have been further from the truth! The two witnesses did not stay dead. We read: “And after the three and a half days spirit of life from God entered into them, and they stood upon their feet, and great fear fell upon those beholding them. And they heard a loud voice out of heaven say to them: ‘Come on up here.’ And they went up into heaven in the cloud, and their enemies beheld them.” (Revelation 11:11, 12) Thus, they had an experience similar to that of the dry bones in the valley that Ezekiel visited in vision. Jehovah breathed upon those dry bones, and they came to life, providing a picture of the rebirth of the nation of Israel after 70 years of captivity in Babylon. (Ezekiel 37:1-14) These two prophecies, in Ezekiel and in Revelation, had their striking modern-day fulfillment in 1919, when Jehovah restored his “deceased” witnesses to vibrant life.
24 What a shock for those persecutors! The corpses of the two witnesses were suddenly alive and active again. It was a bitter pill for those clergymen to swallow, the more so since the Christian ministers whom they had schemed to put in prison were free again, later to be fully exonerated. The shock must have been even greater when, in September 1919, the Bible Students held a convention in Cedar Point, Ohio, U.S.A. Here J. F. Rutherford, recently released from prison, stirred conventioners with his talk “Announcing the Kingdom,” based on Revelation 15:2 and Isaiah 52:7. Those of the John class began once again to “prophesy,” or preach publicly. They advanced from strength to strength, fearlessly exposing Christendom’s hypocrisy.
25 Christendom tried again and again to repeat her triumph of 1918. She resorted to mob action, legal maneuvering, imprisonment, even executions—all to no avail! After 1919 the spiritual domain of the two witnesses was out of her reach. In that year Jehovah had said to them: “Come on up here,” and they had ascended to an elevated spiritual state where their enemies could see them but could not touch them. John describes the shocking effect their restoration had on the great city: “And in that hour a great earthquake occurred, and a tenth of the city fell; and seven thousand persons were killed by the earthquake, and the rest became frightened and gave glory to the God of heaven.” (Revelation 11:13) There were truly great convulsions in the realm of religion. The ground seemed to move under the leaders of the established churches as this body of revivified Christians got to work. One tenth of their city, figuratively 7,000 persons, were so profoundly affected that they are spoken of as being killed.
*** w60 7/15 p. 436 pars. 20-22 The Awake “Faithful and Discreet Slave” ***
20 As we now know, this watchman class of the “faithful and discreet slave” was being cleansed for still greater watchman service in the turbulent years to follow their restoration in 1919. Previously, in the spring of 1918, Jehovah came to his temple of earthly Christian servants for inspection and cleansing. (Mal. 3:1-3) The many bad ones were disfellowshiped by Him and sent away. A loyal remnant were permitted to go through the fiery test where Jehovah and his Messenger, Christ Jesus, (1) tested them by organization arrangements on their loyalty to Jehovah’s organization rather than to human leaders, (2) tested them by service instructions and provisions as to their zeal and devotion to Jehovah’s worship and witness work, and (3) tested them by revealed truth as to their love of it. What a fiery time it was!—See You May Survive Armageddon into God’s New World, pp. 303 to 305.
21 A faithful remnant of some thousands of the “domestics” of the “faithful and discreet slave” class survived this time of testing. From the spring of 1919 forward they began to rise from the dust of inactivity to their new lofty service as watchmen to the world. (Dan. 12:2; Rev. 11:11, 12) The Scriptures also describe them as being clothed with new garments of clean identification to represent Jehovah’s interests in the earth.—Zech. 3:4, 5; see the book Preparation, pp. 55 to 58.
22 Now that the long-expected Kingdom had become an established reality in heaven, surely its growing interests in the earth after 1919 would not be left
The Societys' position, as far as I know, is the "fulfillment" of the prophecies is the confirmation Jesus chose them - so what else would anyone else look for?