Critical Times as Foretold, page-106

John was writing for the people in his time, not unknown generations thousands of years in the future.
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While that is the logical assumption notice what John said in the introduction to his letter.
(Revelation 1:10) By inspiration I came to be in the Lord’s day, and I heard behind me a strong voice like that of a trumpet,

So while he addressed congregations that he sort to encourage that existed in his day, he went on in the rest of his inspired account to relate what Jesus told him would be happening ''in the Lord’s day''. He did this by means of a series of visions. These visions in Revelation are not presented in chronological order. Each has its own time period of fulfillment. Many of the visions echo words of earlier prophecies that provide clues as to their interpretation. For example, Daniel’s prophecy described four fearsome beasts, explaining that these portrayed ruling powers on earth. Hence, we are helped to understand that the beasts of Revelation represent political entities, including those now existing.—Daniel 7:1-8, 17; Revelation 13:2, 11-13; 17:3.
An outstanding example of of being able to anticipate what was to come was when the talk 'Peace, Can It Last' was given in 1942 smack in the middle of WW 2. It was based on this prophecy:
(Revelation 17:8) The wild beast that you saw was, but is not, and yet is about to ascend out of the abyss, and it is to go off into destruction. And the inhabitants of the earth—those whose names have not been written in the scroll of life from the founding of the world—will be amazed when they see how the wild beast was, but is not, and yet will be present.

It was explained that the wild beast that ''was, but is not''(in 1943) was the League of Nations. It ascended ''out of the abyss'' 3 years after the talk was given as the United Nations. We will soon see this wild beast along with political powers(10 horns)that support it , turn on and destroy false religion.
(Revelation 17:16) And the ten horns that you saw and the wild beast, these will hate the prostitute and will make her devastated and naked, and they will eat up her flesh and completely burn her with fire.