If that is the main idea of such a show it is plain dumb. There are ample of categories of crimes that are rarely punished, e.g. white-collar crimes, sexual crimes and war crimes.
I love crime shows that are not as technical and aren't really about the crime but more other stuff. Let's take a classic show like Columbo. It isn't a whodunit, its hero is a badly dressed weird guy who eats eggs on crime scenes and the main part of the show is how this weirdo plays with the murderer whom he somehow instinctively recognizes.
And of course by the far the best crime show is The Wire. Not at least because it is far more holistic than ordinary crime shows and because its main theme of dysfunctioning institutions is more honest and relevant than "let's get the murderer!".