How do TV-news networks make their money, you ask? Commercial advertising, of course. And what are commercial advertising rates based on? Ratings! Viewers! So the more viewers you can maintain, the more money the network makes. It's capitalism at its finest and, if irresponsibly cultivated, its most disgusting.
Therefore, it is in the best interest of the network to keep people watching. There can't be any "slow news" days anymore.
In the "old" days, there were no 24-hour news channels. There was a half-hour a day of Walter Cronkite, who, no matter what was going on in the world, made us all feel like everything's gonna be all right.
With TV news available 24/7, we should be the most well-informed people ever. Instead, we too often get over-reported, sensationalist garbage (CNN) or politically biased lies and nonstop fearmongering (Fox News) that drive the news rather than reporting it. It's all about, "Keep watching us! Keep watching us!"
Follow the money. It's bad, and it's hurting us.