Hugh Nibley explains:
Now it is significant that whereas the name of Sidon enjoys great popularity in the Book of Mormon, in both its Egyptian (Giddonah) and Hebrew forms, the name of Tyre never appears in the book. That is actually as it should be, for in Lehi’s day there was bitter rivalry between the two, and to support the one was to oppose the other. The upstart nobility that were running and ruining things at the court of Zedekiah were putting their money on Tyre, so to speak, and when Nebuchadnezzar came west on the fatal expedition that resulted in the destruction of Jerusalem, one of his main objectives, if not the main one, was to knock out Tyre. Up until quite recently it was believed that his thirteen-year siege of the city on the rock was unsuccessful, but now it is known for sure that Tyre was actually taken and destroyed, upon which Sidon enjoyed a brief revival of supremacy. Now Lehi shared the position of Jeremiah (1 Nephi 7:14), who was opposed to the policy of the court in supporting Egypt against Babylon; that meant that he was anti-Tyre and pro-Sidon.– Hugh W. Nibley, An Approach to the Book of Mormon, 3rd edition, (Vol. 6 of the Collected Works of Hugh Nibley), edited by John W. Welch, (Salt Lake City, Utah : Deseret Book Company ; Provo, Utah : Foundation for Ancient Research and Mormon Studies, 1988), Chapter 7
How would Joseph Smith have guessed any of this? Why does the name Sidon appear in the Book of Mormon but not Tyre?