The Word of God to Jews, Nephites, and the Lost Tribes shared?

“And it shall come to past that the Jews shall have the words of the Nephites, and the Nephites shall have the words of the Jews; and the Nephites and the Jews shall have the words of the lost tribes of Israel; and the lost tribes of Israel shall have the words of the Nephites and the Jews.” (2 Nephites 29:13)
All right so now we have three different groups all of whom are supposed to receive special dispensations of the word of God, Jews, Nephites, and the lost tribes of Israel. I believe this is the first introduction of the lost tribes of Israel theme in the book of Mormon. Later we will learn that these tribes were somehow relocated to the New World, North America, or wherever they are saying the story in this book takes place, before the Nephites. Of course, the tribes were never really lost to begin with. They were conquered by the Assyrians and relocated throughout the Assyrian empire. However, many from these tribes relocated to the southern kingdom during the split so that they could remain faithful to the word of God. Precisely because they knew there was only one temple where the worship of God was acceptable and that was in Jerusalem. (2 chronicles 11:14-16) It is not as if these tribes just up and disappeared in some mysterious fashion and no one knows where they went. And the word that the lost tribes had was the same word that the Jews of the Southern Kingdom had. However, the lost tribes of Israel seemed to have started ignoring that word long before they were conquered and relocated.
Now the fictional Nephites is another story. So far it is apparent that they never received anything from God. The Book of Mormon is the Word of God only where it has been correctly plagiarized. (Much of it is nothing more than a lifting of Isaiah for instance.)
But the more interesting phenomenon here is the failure of this prophecy to take into account the New Testament. I would think that the Nephites would want that too! But then the prophecy too seems to have failed because the Nephites died out long before the Jews settled New York and could have provided them with those other words of God that came after Lehi and Nephi left the shores of Bountiful. You know those little books like Daniel, Ezekial, Malachi etc… God says something somewhere about prophecies that don’t come true. What was that?