Increasingly this has become a historical list because TV themes are disappearing, a victim of very short breaks between programs and the desire of networks to give viewers as few reasons as possible to tune out. The days of the long, leisurely theme song that set the mood -- and perhaps the premise -- for a show (remember the theme for Gilligan's Island?) are long gone. Many of today's hit series, such as Lost and Grey's Anatomy, have no theme at all.
I don't keep up too much with TV, but I had no idea it'd gotten so bad that some shows had no theme song at all. From what I have watched, it sure seems like TV nowadays just sounds boring. Not just the absence of a catchy theme song, but it doesn't seem like music plays much of a role throughout the episode either. Original songs, existing songs, instrumental score -- you hardly hear any of that, like you would have in Miami Vice or The Wonder Years.
Because the lack of music extends throughout the episode, it isn't the result of shorter breaks between programs.
In fact, TV shows are not the only media that have seen their music disappear. Movies used to have hit soundtracks, not just the score but the set of songs that punctuated the action. There was that one lame song from Titanic that became a hit in 1997, but you'd have to go back to 1992 to find several movies that were top 10 at the box office that people remember for their music -- Aladdin, The Bodyguard, Wayne's World, maybe Basic Instinct. Throw in Forrest Gump from 1994 too. But the past 20 years have generally seen music evaporate from the movie-going experience. Either it's not there, or it's not memorable.
Porno movies used to have an original soundtrack too -- nothing special of course, but it did its job of setting the mood and helping you to forget yourself. Sounds better than some fake screeching from the girl and dorky remarks from the male crew. Again, no big loss to society; the point is to establish the breadth of the disappearance of music in visual media, all during the same time frame.
Shit, MTV hasn't played music on television for 15 years.
And what ever happened to catchy jingles in TV commercials? "The best part of wakin' up, is Folgers in your cup!" Good ol' 1984, man. No one expects commercials to sound mind-blowing, but at least don't make them grating on the ears ("Aflaaaaac!"). Now the only ones that don't sound annoying make use of oldies from the '80s, like a recent ad for Reese's Peanut Butter Cups that featured "(Feels Like) Heaven" by Fiction Factory.
And of course pop music in its own world has become progressively lamer over the past 20 years. Musicians just can't do what they used to, whether it's in their own songs, jingles, TV theme songs, or movie soundtracks.
Now, onto those theme songs that became Billboard hits. Below are two charts showing how many songs charted, by 5-year periods. The number shows the highest position it attained. I included more than one recording of the song, by different artists, if they came out during the original run, but not if they were covered later on. That only excluded a few; most theme songs were hits when the shows themselves were hits.
Note that there are no entries after 1995, when the Friends theme caught on. Again this is from the 2007 edition, though I doubt anything in the last 5 years has charted. Technically, "Bad Boys" came out in 1987, but was not famous at all. It only charted in 1993 after it was released as a single following the popularity of Cops. So it's more or less an original theme song -- one that just about all audience members would not have heard before.
Almost all of the hit theme songs come from rising-crime times, no surprise there. They don't steadily rise in frequency, though, nor would an index that weighted each song based on its chart position. The peak is the later half of the '70s, both by frequency and by how highly they ranked.
I think if you added in catchy ad jingles, porno music, and especially movie soundtracks, you would see a steady rise through at least the mid-'80s. It's tempting to conclude that within the rising-crime surge of TV themes, the periods of greater production were when pop music wasn't quite as happening, leaving more musicians free to write the TV themes instead.
You do have to control for how good the rest of pop music was, though. If it was great, then a halfway-catchy TV theme probably would not have been able to defeat the competition for a spot on the Billboard charts. There were plenty of enjoyable theme songs like those from Cheers, Family Ties, Golden Girls, Alf, just to name a few, that could have squeaked in if the '80s hadn't been churning out one great pop song after another. But when the catchy theme for Laverne and Shirley hit the charts in 1976, it only had to contend with Barry Manilow, Bay City Rollers, and Wings.
Heh, that's as good a note as any to end on. Just goes to show how boring the culture has become that it can't even make a groovy, upbeat theme song anymore.