I thought Revelation was written by John?
No, it isn't. All the info was in the New Testament the whole time. There may have been a recent emphasis, but it's not some new invention.
Just off the top of my head, what about the verses in the New Testament that talk about two women grinding flour--one will be gone and one will be left? That isn't even in Revelation, but somewhere else in the New Testament.
36"No one knows about that day or hour, not even the angels in heaven, nor the Son,[6] but only the Father. 37As it was in the days of Noah, so it will be at the coming of the Son of Man. 38For in the days before the flood, people were eating and drinking, marrying and giving in marriage, up to the day Noah entered the ark; 39and they knew nothing about what would happen until the flood came and took them all away. That is how it will be at the coming of the Son of Man. 40Two men will be in the field; one will be taken and the other left. 41Two women will be grinding with a hand mill; one will be taken and the other left.
42"Therefore keep watch, because you do not know on what day your Lord will come. 43But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into. 44So you also must be ready, because the Son of Man will come at an hour when you do not expect him.
Here is the link to Matthew, Chapter 24. If the link doesn't work, of course you can look it up in your own Bible.
Sorry, but you are wrong. It was the Lord Himself that spoke these words to the Apsotle John who recorded them:
Because thou hast kept the word of My patience, I also will keep thee from the hour of temptation, which shall come upon all the world, to try them that dwell upon the earth. Rev. 3:10