Even though Nephi’s dream showed a distant future, it is probable that Nephi did not fully understand the true length of the time involved. Nephi speaks to what must have been one of his brothers’ concerns: When would they be gathered again? They knew they were being scattered. Laman and Lemuel were obviously anxious to return to Jerusalem. They likely saw the promise of the gathering as a time when they, or perhaps their close descendants, might return to the Jerusalem that they hadn’t wanted to leave.
Nephi might have felt some of that longing, as he and Jacob both teach of the gathering. The theme of the gathering disappears in later writers who had not known the Old World. That theme fades from the Book of Mormon after those two brothers who had known the Old World. It is probable that for those who knew only the New World, there was no longing for a reunification with a people they had never known and could only see as foreign.