One of America’s most beloved TV shows in recent years, CSI: Crime Scene Investigation, ended its 15-year run on Sunday night with a feature-length special, ironically titled “Immortality.” CSI quickly became America’s most-watched show when it debuted in 2000, but like so many former hits, it faded out after years of declining ratings and multiple attempts to reboot its cast. The finale got a respectable 12 million viewers, but was beaten by ABC’s new show Quantico, and barely matched its final season’s average viewership.
The finale special mostly functioned as a piece of fan service—the most a network can do for a show that once served as its flagship product. The episode brought back all of CSI’s original characters and had the central pair Gil Grissom (William Petersen) and Sara Sidle (Jorja Fox) resolving a long-dangling romantic subplot that was all but abandoned years ago when the actors moved on.
It also served as cross-promotion for the show’s one remaining spinoff, CSI: Cyber, with Ted Danson’s character joining the Cyber team after five years manning the ship on CSI. Danson’s presence underlined the central paradox of maintaining such a long-running show: As CSI stayed on the air, its actors became more and more expensive, but when the original cast left, CBS needed new stars to draw new viewers. Laurence Fishburne was the first replacement, then Danson, but they couldn’t stop a ratings slide (the show averaged 26 million viewers in 2005, 15 million in 2010, and 11.5 million in 2015). In the end, those steadily sagging ratings couldn’t justify rising costs.