As long as the people worshipped God he would have retained the dynasty of King David and history permitting, the chosen descendants of King David would have been the subsequent kings of Judah. Follow Jesus' family tree in the first chapter of Matthew's gospel, and there you find Joseph, Mary's husband. Joseph could have been the king of the tribe of Judah.
What if Joseph had been a king? Would he still have married Mary, or would he even have wanted to marry Mary? If they did marry, and Mary was the mother of Jesus, how would he have been brought up - in a palace?
From the Old Testament prophets we know this was not going to happen, but when I realised that Joseph would have been in line to be a king, I then started thinking........