User blog comment:LuNa/Anime Ending?/@comment-2.101.63.108-20130304231349/@comment-1776824-20130304235814

Because they realize nobody wants them to pull a Naruto/Bleach and make completely unrelated filler episodes in the middle of an arc, or create a new arc in the middle of an arc. Most people hate it. They may like the episode, but they hate that it takes away from the story. I know I do.