Zechariah was of the tribe of Levi. He was an old man. God began his work there. Despite the age, God was able to produce new growth in his son John.

Jesus was not of Levi. Matthew shows his adoptive father was of David/Judah. Luke shows that his mother was likewise from the same line.

God worked among the old ordinances, and he was establishing something new. John, a Levite prophet put the dead works of the Jewish priestly class and people on notice. While they claimed to speak for God and preserve his laws, scriptures, feasts and ordinances, they failed to know God or recognize his messengers. It was these "chosen" people who excommunicated and then killed them both. They both had reception among the commoners, but Nicodemus was the only secretive hearer among the leadership.

Most Old Testament prophets among the Jews came outside of the priestly tribe of Levi. John, while of that tribe, was not in any position of authority.

The kingdom transitioned from the Levites from John to Jesus, the old bottle could not hold the new wine. The wine was good in either bottle. A new people would be given an opportunity.