First of all, TV announcers do not always explain everything that is going on because we can see that for ourselves. Explaining everything would be redundant and we, as TV watchers, don't need everything explained to us as radio listeners do, since they cannot see what is going on. Unfortunately, the TV guys have stepped up their in-game stories to the point that it is really annoying, and although we can see what is going on, some things have to be explained. I can see the point of the stories since silence would be worse during the game, so the crew has to be aware how much is too much, and most broadcasting crews have yet to figure that out.