Jerusalem has indeed “drunk at the hand of the Lord the cup of his fury” and been “wrung out” to the very last drop. As Isaiah later tells us, “She hath received of the Lord’s hand double for all her sins” (Isaiah 40:2).
But whyso much suffering, and why for so long? The Lord declared, “As one generation hath been destroyed among the Jews because of iniquity, even so have they been destroyed from generation to generation according to their iniquities” (2 Nephi 25:9). If they continue to reject their God, they continue to suffer for it.
Verse 18 explains that there is no priesthood leadership in Judah; there are no prophets.