Behold, the days are coming, says the Lord,
when I will conclude a new covenant with the house of Israel and the house of Judah.
It will not be like the covenant I made with their fathers the day I took them by the hand to lead
them forth from the land of Egypt;
From this perspective we can be astonished that David's heirs ruled as long as they did, especially in that part of the world.
Jesus' Twelve Apostles survived only a little while. After the death of Judas Iscariot, the apostles invited Matthias to take his place; but as a group they disappeared when James (the Greater) was beheaded. No one was appointed to take his place and the twelve did not appear as a group even when Peter, James (the Lesser) and Paul met in Jerusalem for the first "council" of the Church.
Through all these historic changes the Lord is faithful to his word, "Remember, I am with you always." He had promised his abiding presence to Abraham and his descendants, to Moses in the desert, to David and his heirs, and to the Church. Human institutions appear and disappear but the Word of God abides forever.