I think you're over-simplifying it a little. When long, in depth stories are aired, our viewership tends to drop off the map. I wonder if people just don't want to see anything that serious on the news anymore (I blame the generational change - mostly older people watch the news nowadays). If viewership drops, then we have a very difficult time keeping financial supporters happy (advertisers - they are the ones with ALL the power in the news business, if they decide to pull out of sponsoring a segment, that segment or show will probably be axed).
Besides, if people wanted in depth coverage with as little political bias as possible, all they need to do is watch PBS - and the best part is that it's free for all. Of course no one watches, and why should they, it has no cool explosions or flashy graphics. People in general don't care at all about what is happening outside of their town or state, and possibly country (but that's still stretching it).
It's a sad state, but it's a state we're living in.
By the way, I have a Master's degree in Communication focusing on Mass Communication. I've done some studies on the spiral of silence theory (which could be applied to this particular problem), Cultivation Theory, Uses and Gratifications Theory (an aspect of the Hypodermic Needle Theory), Priming, Elaboration Likelihood Model, Framing, Agenda-Setting Theory, Cognitive Dissonance Theory, and Social Cognitive Theory. Those are just the ones I've worked with, there are many more.
