Abinadom makes explicit the reason that he and his immediate ancestors have written so little. He has been intimately involved with war and contention, and recording those is the purpose of the large plates. Therefore, he has little to say. What he does say touches, if only briefly on the sacred. What he says is that he knows that there are revelations, but they have already been written. Perhaps he was saying that the available scriptures held the gospel, and that there was no new revelation of doctrine.
Throughout history it has been thus with the gospel. The scriptures provide the foundation, and humankind can build their spiritual lives upon that foundation. There is not always change. At times, what has been given is sufficient. In Abinadom’s words, “that which is sufficient is written.”