I think we might be reaching that point with cop shows.
I love cop shows but as I flipped through my PVR, I realized that almost everything I watch is a cop show. There’s Continuum, Fringe and Grimm, all cop shows with a science fiction or fantasy bend. Longmire, The Glades and Breakout Kings, A&E’s interseason offerings. Castle, a funny cop show with a romantic twist. And the classic Law and Order and CSI franchises. Even House was often referred to as a medical cop show with the disease as the bad guy.
First of all, this proves I watch way too much TV. But as I started searching for something which wasn’t a cop show, I found my options were basically limited to reality TV programs and sit-coms. If I want an hour long show with witty drama and interesting characters, I’m apparently stuck with watching cop shows. Maybe I'll get lucky with September's new offerings.
My husband points out that ten or twenty years ago, everything was a medical show. It’s not surprising that we end up with a glut of repetitive programming. Studios like predictable success and if something has been working, they’ll stick with it. Something different may be brilliant but it might also prove to be a black hole.
I’m taking a lesson as a writer. It’s easy to end up falling back on the same repetitive patterns over and over again, making the same choices because they’ve worked before. I’ll have to be careful not to fall into the trap.
Interesting side point: the prevalence of westerns in the early years of TV is one of the reasons why calling a sci-fi show a "space western" is such an insult. Sci fi audiences got tired of seeing show which were basically westerns with aliens.