A few weeks ago I wrote about U.S. science fiction television series' that I watched on French television during my formative years. One such show, Voyage to the Bottom of the Sea, was bookended by a terrific theme tune: Composed by Paul Sawtell, "The Seaview Theme" painted an aural picture of seafaring adventure (even if that adventure was at times ridiculous).
It is often said that television has entered a new "golden age" *, fine (I'll stick with my paper books), but one thing missing is the title theme; that piece of music that encapsulates the show's idea -- its heart and soul.
The answer is academic: running times for one-hour programs now are short and a one-minute theme tune and title sequence eats into the story to be told. In addition, binge-watching is common, and having the opening theme play every 40 minutes is not needed given the context.
The common default today of using songs in dramatic television is cheap. Indeed, having at least the "Cheapo Johnny Cracker Orchestral Theme" play about would be something. Anything.
* TV addicts say that.