Jesus Christ's claim to the throne is God's claim to the throne. He doesn[t have to inherit anything that is already His as another poster has pointed out. The elect that belong to Jesus are the elect that belong to Jesus. The true throne never changes.
Zedekiah's claim to the "throne of David" King of Judah, was every bit as real as any other king put up there by the Lord. If God didn't enthrone him who did? Nebuchadrezzer did, but whose servant was he? This is sealed when Ezekiel refers to him as the "Royal Seed" that was taken away to Babylon in the parable of Chapter 17. And he is the one referred to, not Jechoniah or the son, who sat on the throne for 6 months after the curse was given.
To show just how unimportant the "Throne" was to God, He even let the AntiChrist and his son sit on it, while the True King walked the earth.
The irony of course with Jeremiah, as with the other prophets, is that the people constantly reject the Word of God, whether it's the Torah or Jeremiah. If you are going to feed them, feed them bread not manure.
antichrist sat on it??????? please explain