Well, no, he didn't. He just said that the seven-hilled city would be destroyed. No whores or Babylonians mentioned.
In context, that's probably Rome, which is certainly famous for its seven hills.
John called it in Rev 17, "the city that rules over the kings of the earth."
Are you sure it's the same "it"? John also calls it "the great city," (17:18) and in 11:8 he speaks of a "great city" which is clearly Jerusalem.
That phrase "the great city" is used several times in the OT in reference to Jerusalem. Compare the language of Rev 17 to that of Jeremiah 25, which is certainly speaking of Jerusalem, and the evidence is even clearer. (Rev 17 is also "cribbing" from some texts in Ezekiel which refer to the destruction of Jerusalem by the Babylonians.)
And, BTW, ancient Jerusalem is also a "seven-hilled city".
Rev 17: 1 One of the seven angels who had the seven bowls came and said to me, "Come, I will show you the punishment of the great prostitute, who sits on many waters. 2 With her the kings of the earth committed adultery and the inhabitants of the earth were intoxicated with the wine of her adulteries." 3 Then the angel carried me away in the Spirit into a desert. There I saw a woman sitting on a scarlet beast that was covered with blasphemous names and had seven heads and ten horns. 4 The woman was dressed in purple and scarlet, and was glittering with gold, precious stones and pearls. She held a golden cup in her hand, filled with abominable things and the filth of her adulteries. 5 This title was written on her forehead: 6 I saw that the woman was drunk with the blood of the saints, the blood of those who bore testimony to Jesus. When I saw her, I was greatly astonished.7 Then the angel said to me: "Why are you astonished? I will explain to you the mystery of the woman and of the beast she rides, which has the seven heads and ten horns. 8 The beast, which you saw, once was, now is not, and will come up out of the Abyss and go to his destruction. The inhabitants of the earth whose names have not been written in the book of life from the creation of the world will be astonished when they see the beast, because he once was, now is not, and yet will come. 9 "This calls for a mind with wisdom. The seven heads are seven hills on which the woman sits. 10 They are also seven kings. Five have fallen, one is, the other has not yet come; but when he does come, he must remain for a little while. 11 The beast who once was, and now is not, is an eighth king. He belongs to the seven and is going to his destruction. 12 "The ten horns you saw are ten kings who have not yet received a kingdom, but who for one hour will receive authority as kings along with the beast. 13 They have one purpose and will give their power and authority to the beast.
14 They will make war against the Lamb, but the Lamb will overcome them because he is Lord of lords and King of kings--and with him will be his called, chosen and faithful followers." 15 Then the angel said to me, "The waters you saw, where the prostitute sits, are peoples, multitudes, nations and languages. 16 The beast and the ten horns you saw will hate the prostitute. They will bring her to ruin and leave her naked; they will eat her flesh and burn her with fire. 17 For God has put it into their hearts to accomplish his purpose by agreeing to give the beast their power to rule, until God's words are fulfilled. 18 The woman you saw is the great city that rules over the kings of the earth."
Cincinnati is also a 7 hilled city, but it doesn’t rule over the kings of the earth.
Neither does Jerusalem.
I just looked at a topgraphic map and ancient Jerusalem was not built on 7 hills. There are only 3 hills inside the Old City, and perhaps 4 if you include the ridge that runs up to the supposed site of the Davidic palace.
100 AD Rome, on the other hand, does have at least 7 hills inside the walled-in area. Again, this is an issue of how you count the humps of a ridged mountain. In any case, they are inside the city while Mt Olives is outside of Jerusalem.
The Mount of Olives is outside the city (as evidenced by the map, and also by the gospel accounts themselves.)
One attempt I saw to come up with 7 include the Mount of Olives and tried to make the one Mount into 3 hills.
Now I’ve got to find a topo of the Rome of St John. One account I read said that when the city was founded the founders intentionally put it behind 7 hills to protect it from the sea. It says they intentionally named it “7-Hilled City” to draw attention to the symbolism of the number 7.
That raises the issue of Rome 17 saying that the sea captains of the world would stand off from the destruction of that city and lament its loss. It appears to be a port city.
That does not describe Jerusalem which is 40 rough, highland miles inland as the crow flies. Rome is about 30 miles across a less highland region from the coast; again as the crow flies.
Whatever else we might say about the destruction of the 7-hilled city, the destruction does not seem to be of a type that endangered the lives of those ships standing off the coast.