In May 2010, as has been pre-arranged by the creators of the show, ABC's Lost will air it's final episodes. Similarly, the heads of the network will determine whether or not they have a series to replace it with. The odds are not good, as both of the shows they tooled for it's audience, Flashforward and V are each barely averaging around 5 million viewers per episode. Though the network may decide to spare one or the other, it seems likely that both shows will join Invasion (2005), The 9 (2006) Daybreak (2006) and Life on Mars (2008) in the increasingly crowded attic of failed mythology series--- and those were only ABC's attempts.
Perhaps ABC should have learned from the failures of Fox. For over a decade, they tried in vain to come up with a series that could attract the same market as The X-Files, often in he same Friday night time slot. Over a dozen series tried to fit in during the series nine-year run, including two series by creator Chris Carter--- Millennium, which ran from 1996-1999, supposedly to keep Carter working for the X-Files, and The Lone Gunmen, an actual spin-off that premiered by the time energy was all but bled out of the original. Even now, when they premiered Fringe, a series from Lost creator J.J. Abrams typewriter, the end result was the same---small devoted following, but no ratings smash. (Admittedly, airing it 9 P.M. Thursdays against Grey's Anatomy and CSI hasn't helped.)
While there are a lot of reasons why all of these shows never enjoyed the success that these groundbreaking shows did, perhaps these repeated failures should serve as proof of a larger truth --- the very makeup of these series are not designed for any kind of long-term success. For starters, networks no longer have the patience to let a series like X-Files premiere and slowly build up buzz. Instant success is the only option possible for any new show, or series' are tossed to a new timeslot or--- more frequently--- cancelled after a handful of episodes.
However, one could make the argument that the same success that built the X-Files eventually led to the series' imploding. When Fox moved the series from the relatively crowded Fridays to the then all-but-empty Sunday nights at 9, the series audience nearly doubled to more than 25 million viewers a week. But because of it's rating, Fox extended the life of the series long beyond the original five years Carter wanted the series to run. The more Carter tried to extend the mythology that framed it, the less fathomable it became to the average viewer. Only because of the existence of standalone episodes did the series work at all. By the time it ended its TV run in 2002, even Carter had to admit that he had "stumbled and fell" in trying to map out a path for the series to take.
Lost endured a similar arc. After the landmark first season in which the show averaged between 12 and 15 million viewers, and won the Emmy for the Best Drama, the series leapt to number one in the Nielsen ratings. But as soon as the show's ratings exploded, a huge amount of critical and fan backlash emerged, partly because new viewers were confused by the shows mysteries, and because old viewers didn't like the new pace the show had taken. Creators Carlton Cuse and Damon Lindelof eventually worked out a plan for the course of the series, but by May 2007, the ratings were little more of half of what they were.
Even mythology series considered successful only worked on a limited basis. Joss Whedon's Buffy the Vampire Slayer and Angel were big successes --- for the WB, a network whose average ratings were so low, it doesn't exist anymore. Future efforts for Fox such as Firefly and Dollhouse had ratings that by normal network standards were low, but would have been at least passable on say, the CW. Like all of Whedon's shows, it had a devoted internet fanbase, but that did not translate into the necessary audience.
Perhaps this reaches the foundation of a mythology series. Every major show has had a certain devoted fanbase that will stick with the show through thick and thin. The X-Files started average about 8 to 9 million viewers an episode, and that's roughly where it was when the series came to a conclusion. Lost's ratings have basically stuck around the same level for the past four years--- roughly 9-10 million viewers a week. They are extremely devoted fans, but the nature of the show's structure has stopped the show from ever earning new viewers each seasons, and even a slight drop each season after the early flurry of interest.
The roots of these problems with these mythology shows may fall back to all of these programs ancestors--- Twin Peaks. Recently commemorated in the media for it's twentieth anniversary, one can't help but wonder if the people at ABC really learned their lessons with this show's meteoric rise and fall. Debuting to some of the most extraordinary praise, it's ratings for it's initial eight episode run were excellent even by the higher standards of the early nineties and receiving fifteen Emmy nominations. But the buzz began to collapse after the awards, where they won only two trophies for technical awards. The reviews and ratings of the show never recovered, even after the show's central mystery---- who or what killed Laura Palmer--- was resolved. ABC would make a series of questionable programming decisions in the early nineties, but cutting a show that critics had started to openly mock seemed an easy one.
The main reason X-Files managed to avoid Twin Peaks fate was the explosion of the Internet as a place where fans of TV shows could gather. Hundreds of websites would spring up devoted to the show, and continue to flourish over eight years since the series was cancelled. In those early days, Fox was not kind to these sites, shutting many down for copyright infringement. By contrast, Lost creators would openly woo and encourage the development of similar sites, with creators Cuse and Lindelof often going online willing to discuss and enflame further mysteries of the shows with the devoted followers. Other shows creators (particularly Joss Whedon) would do the same, but with nowhere near the success that they have anywhere else.
But perhaps the real reason that mythology shows haven't succeeded as well because they expect the opposite of what conventional wisdom should work. The main reason that police procedurals like the CSI or Law & Order franchises work is because they have a formula of resolving everything in sixty minutes or less. The There is an audience out there for complicated shows with ambitious capabilities for telling a story over a period of months or even years, but historically, they've never been as large as those of more conventional shows. Why else would CSI and Grey's Anatomy have more than triple the ratings of Fringe, a dramatically superior but far more convoluted program? Critics may say these kinds of programs have inferior narratives and no direction, but maybe the answer is a lot simpler than any mystery these shows produce. The average viewer wants simpler. Successes like Lost are aberrations, not the norm, and the odds a similar success ever being developed are, well, like figuring out what is up with that island in the Pacific.