In the reality TV universe, extreme-adventure shows such as "Survivor" or "The Amazing Race" -- or France's now disaster-hit "Dropped" -- are like former sports stars: a little worn out but still popular.
With their exotic locales, high-end production values and faded celebrities in search of a second wind, various programmes of the genre have been made for more than a decade.
Audience interest in them is flagging to different degrees in different countries, as talent-related shows like "The Voice" and manufactured celebrities like Kim Kardashian steal the limelight.
"Survivor" was the first of the type. The Robinson Crusoe-style struggle on an island started in Sweden and spread to the US and many other countries sometimes under other titles.
The number of American viewers for "Survivor" has dropped from 53 million when its US run started in 2000 to just six million in the latest season.
In France, though, the "Survivor" franchise retitled as "Koh Lanta" is still going strong on leading commercial network TF1. Its last season pulled in more than 30 percent of total viewers, or seven million people on average.
- 'Gladitorial' appeal -
Experts say the enduring attraction of the shows lie in the producers' canny techniques to enhance viewer identification with the contestants, the heightened drama, but especially the exoticism and resourcefulness on display.
"The rivalries, the acclamation of physical prowess, the clans... we're in a modern gladiatorial combat," explained Isabelle Veyrat-Masson, a historian and media sociologist and author of a history of French television.
Christophe Nick, who made a documentary about excessive reality shows in which contestants were subjected to electric shocks, went further, suggesting it was "basic instinct TV".
"Instead of average people, they take athletes able to endure extreme conditions. It's close to ultimate fighting," he said -- though he underlined that the helicopter accident that killed three French sports figures in Argentina had nothing to do with those sort of extreme physical tests.
In any case, noted Bertrand Villegas, a professional observer of TV programmes around the world, interest in the extreme-adventure format is waning.
"France and Scandinavia are the last big markets for these adventure games," he said. "The segment is no longer dynamic, and it's not as vital to the global entertainment industry as singing competitions" like 'The Voice'".
Not only that, the adventure shows are relatively expensive, having to spend big to send celebrities to far-flung corners of the planet. French media estimate "Koh Lanta" costs between 600,000 and 800,000 euros ($650,000 and $850,000) per episode.
- Variants being tried -
Variants are seeing the light of day, but aren't getting much traction.
"Utopia", for instance, brings together a cast of people in a remote location to live together and try to create their own society.
The show was created by the Dutch billionaire behind "Big Brother", John de Mol, but the US version that started late last year has been poorly received.
US network Discovery swapped celebrities for senators in its "Rival Survival", which strands a Democrat and a Republican lawmaker on a Pacific island.
"In the area of adventure games, it's become tough to innovate, so they are trying different formulas. But if you want it to be an adventure game, there needs to be risk-taking," said Nathalie Nadaud-Albertini, a French sociologist and specialist in reality TV shows.