From what I've heard, there was some accountability this year but, as others have pointed out, there are limits to what Holmoe can do.
One very possible scenario, Holmoe told Bronco to get rid of Howell and Bronco declined, that Bronco threatened to quit if Howell's contract was not renewed. Holmoe, rather than forcing the issue, demanded changes in the defense and that Bronco take the defense back over (which has happened).
While Howell has the same title, he did essentially "lose his job" as Bronco is effectively the DC again, so there was some accountability. As others point out, we just don't know what restrictions Holmoe is under or what issues there might be for BYU if Bronco left in January.