The contrast between the details of the battles between Shared and Coriantumr only serve to highlight the absence of such stories for the earlier history. It would appear that when Ether wrote, he was most interested in the final days, and therefore only gave the bare bones of the history needed to get to the end.
Once again, however, it is emphasized that “there were robbers, and in fine, all manner of wickedness upon all the face of the land,” even though we are given no details of what they are doing and how they are involved. Their presence alone is sufficient to let the reader know that the end is coming.
This is not the end of a chapter in the 1830 edition of the Book of Mormon.