Oh but Alouette, when Ezra and Nehemiah came to Jerusalem from Babylon to rebuild that temple they had no one of the tribe of Levi with them. They had to send back for a member of the tribe of Levi.
The 'priest' became lazy and allowed servants to do what was required of them to do. It is written.
And how would you know precisely what is Written? Can you read the original Scriptures in Hebrew and Aramaic or only some translation of another translation?