Alma 45

I believe that Mormon's abridgment was written especially for our use in our day. As we liken the scriptures unto ourselves, as counseled by Nephi, we should carefully listen to the last words of Alma to his son, Helaman -

"...Thus saith the Lord God—Cursed shall be the land, yea, this land, unto every nation, kindred, tongue, and people, unto destruction, which do wickedly, when they are fully ripe; and as I have said so shall it be; for this is the cursing and the blessing of God upon the land, for the Lord cannot look upon sin with the least degree of allowance." (Book of Mormon | Alma 45:16)

This statement was for all nations that would live on this land. Then looking at his own people, Alma prophecies -

"Behold, I perceive that this very people, the Nephites, according to the spirit of revelation which is in me, in four hundred years from the time that Jesus Christ shall manifest himself unto them, shall dwindle in unbelief." (Book of Mormon | Alma 45:10)

Because of his people's wickedness and disbelief, that the -

"...great day cometh, behold, the time very soon cometh that those who are now, or the seed of those who are now numbered among the people of Nephi, shall no more be numbered among the people of Nephi.
14 But whosoever remaineth, and is not destroyed in that great and dreadful day, shall be numbered among the Lamanites, and shall become like unto them, all, save it be a few who shall be called the disciples of the Lord; and them shall the Lamanites pursue even until they shall become extinct. And now, because of iniquity, this prophecy shall be fulfilled." (Book of Mormon | Alma 45:13 - 14)

That prophecy was fulfilled. And so shall it be to this generation when we are fully ripe with no righteous saints among us that that same prophecy will be fulfilled in our day.