Why TV Can't Tell Stories Chronologically

The use of the flashback in telling a story has been around forever. In the hands of skilled storyteller, it can be a very effective device. The author wants to control how much the audience knows, and at what point everything can be revealed. However, in modern TV shows, the narrative flashes back and forth so often that the viewer may end up dizzy. These multiple timelines can keep us guessing, or make us just give up. 

Is this just a trend in the art of storytelling? Or is it a way to pad out a too-short main story and make it last through the planned season? Or is it just fun for the cast and crew? The difference between a flashback as a stunt or an effective storytelling device is how necessary it is to making the story coherent and satisfying to watch or read.