Turns out they were wrong. As two long weeks of I'm A Celebrity... Get Me Out Of Here! have shown, millions are willing to spend hours watching a bunch of wannabes, trying-to-bes and used-to-bes cooking over a campfire – especially if there is an opportunity to lock Gillian McKeith into a box of rats and bugs at the end of it.
Reality television is very far from dead. As far as viewing figures go, it is in rude health. Over 10 million people tuned in to see Nigel Havers, one of the more familiar "celebrities" in the jungle encampment, deciding to leave the show. He objected to the Kangaroo Court trial, where his fellow celebrity campers would be given an electric shock if they failed to complete their task. "I'm not up for it, I don't do electric shocks so I'm leaving," he said on air. "I cannot waste another second of my life."
The audience – which would probably have no qualms about inflicting said shocks, in the style of the infamous Milgram experiment at Yale, from their remote controls if only the technology existed – does not seem to be missing him too keenly. They have another target in mind.
This season's IACGMOOH has all been about inflicting the maximum amount of pain and humiliation on McKeith, the questionably qualified nutritionist who made her name by inspecting fat people's faeces on television.
McKeith made the mistake, in her pre-series interview, of admitting to being terrified of creepy-crawlies, water, heights, everything that moves and life without regular mango smoothies. Armed with this knowledge, the show's audience has turned on her, voting for her to face eight bush-tucker trials. For these sofa-bound sadists, this is both the highlight of the show and the perfect opportunity to turn the tables on McKeith. What could be more satisfying than making the vegan who urges the overweight to swap their cream cakes and curries for grilled mackerel with steamed kale eat bull's tongue, beach worms, crocodile eyes, crickets, cockroaches and crocodile penis? This diet is not agreeing with McKeith. She has already fainted live on air, been given oxygen and claimed to be pregnant in a blatant play for sympathy – all while the show's producers punch the air. These are the moments – television's equivalent of the audience in the ampitheatre giving the fallen gladiator the thumbs-down – that keep viewers coming back in their millions.
"I'm A Celebrity is qualitatively different to Big Brother," says a TV insider who worked on the latter for 10 years. "It is more in the style of the medieval stocks. Pain is the key as to why it is different from others in the genre. It is becoming the modern equivalent of the Tyburn executions."
It is this unprecendented level of cruelty that is threatening to tip IACGMOOH beyond entertainment and into the bear pit of cruelty. The desire to punish celebrities for being craven enough to sign up for the show in the first place, and then revel in their discomfort as they are lowered into a tunnel of rats (the relatively innocuous Jan Leeming, in 2006) or forced to eat kangaroo sphincters (Katie Price in her second stint in the jungle, in 2008) is not new. Electrocuting them is – as is the audience's dogged determination to use their voting powers to bulldoze through their own sadistic agenda. No amount of fainting and histrionics is going to stop them.
Viewers have become incredibly sophisticated and selective in the way they treat the objects of their disdain. Last week they voted to keep McKeith on the show, presumably because they find participating in her distress highly enjoyable, by pressing a red button on their remote control. How on earth did we get here? When did the bloodlust of the Roman Colosseum become acceptable family entertainment? The torturing of McKeith is, perhaps, simply part of the logical progression of reality TV.
In the decade since BB arrived on our screens, the media landscape has changed beyond all recognition. The runaway success of the first series, (the one with Nasty Nick, won by builder Craig Phillips) took everyone by surprise. The tabloids were quick to pick up on the characters and the dramas as a great way to fill the long, empty pages of summer and it became, to use an exciting new phrase of the era, watercooler television. Heat magazine, then also fresh, shiny and an acceptable guilty pleasure, picked up any possible slack.
Suddenly there was a whole new way of programming, made possible by the replacement of expensive film by cheaper video formats. The genre splintered, as producers started using real people and reality techniques in makeover shows, life-swap shows, find-a-new-model shows.
In its wake, the new generation of sub-Heat celebrity magazines were more than happy to pad out their pages with these readily available, publicity-mad "stars".
The possibility of public voting opened up a whole new area, whereby the reality element – inasmuch as the show followed a group of real people, often living together in close quarters – could be tied into the old-fashioned talent show format. As a result Pop Idol, Fame Academy, X Factor and Britain's Got Talent, all supported by spin-offs, extensive official and unofficial internet activity and screeds of red-top and gossip mag coverage, have had a giant hogweed effect on popular culture, dominating the landscape, denying sunlight to anything small and fragile trying to grow nearby.
What other creaky old concepts, they wondered, could be revived by the addition of three nippy-tongued judges and a phone number on the bottom of the screen? Strictly Come Dancing, the reality version of the BBC's unlamented ballroom dancing show, was the ratings-hoovering result.
So while Big Brother might have gone, its descendants are everywhere. The genres divide, sub-divide and cross-pollinate at a terrifying rate.
America has gone nuts for Bridalplasty, in which six women planning their weddings compete to win plastic surgery for their big day. It has also seeped into the political arena, with Sarah Palin starring on her own fly-on-the-wall series while her daughter, Bristol, who makes John Sergeant look like Darcey Bussell, recently was third in Dancing With the Stars.
No area of life is safe from the clip-on microphone and hidden camera. Shows such as The Apprentice, Dragons' Den and Undercover Boss take them to a business setting. With no voting and no eating worms, they form the respectable face of reality television (although there is certainly an element of cruelty in watching the smug, hair-gelled upstarts of Sugar's toady army trudging the streets of Hamburg, trying to punt bratwurst-flavoured crisps).
They also show that the genre is not completely without merits. The Secret Millionaire, in which a loaded entrepreneur, often from humble stock, leaves his or her flat screen television-filled mansion to spend a week in some dismal corner of Broken Britain, is rarely less than moving. Their journey - reality TV is nothing without the journey - not only shows the humbling effect of living on baked beans in a maisonette, but gives viewers a glimpse of genuinely ordinary people, ones who have not signed up to be on telly, doing extraordinary and often thankless work to help others who are even worse off then themselves.
Given the lack of opportunities for cruelty, prurience, voyeurism and schadenfreude, Secret Millionaire gets about a tenth of the viewing figures of IACGMOOH. It does not feature on the front pages of Now!, Take A Break! or any of the other exclamation mark titles. These are full, however, of stories and personalities from the lower end of the reality spectrum. Nicky Hambleton, once presenter of Channel 4's 10 Years Younger, may dispense fashion tips, Gok Wan is bound to be there in some shape or form, McKeith, before she was dropped by Channel 4, would have suggested intriguing new ways with beansprouts.
Then there will be stories about the reality series that are currently running. These may, confusingly, feature people who are famous for having previously appeared in other reality series. (Currently in the jungle with McKeith are former BB contestant Alison Hammond and X Factor veteran Stacey Solomon.) There may also be paparazzi pics of other people who have appeared on these shows in the past, attending an awards ceremony, or shopping in Tesco. If every other reality show followed BB into the abyss, not only would the TV schedules shrink like the winner of charming American series Biggest Loser, but whole magazines would be empty and columnists, bloggers, Twitterers and the 378,616 people who have signed up for the Facebook page "Quick, get the oxygen out, Gillian McKeith's just touched a leaf" would have to find something else to do with their lives.
The feeling from the industry, however, is that they should not be too worried. "There will definitely be more celebrity bear-baiting," says the BB insider. "As times get harder, people get harder. They want blood. If you haven't got a job, do you want to watch people get paid to swan around, getting a suntan, or do you want to watch them being made to suffer?"
The problem, as Mike Bolland, former commissioning editor at Channel 4 identifies, is that, with each returning series, the producers have to squeeze the format a little harder to keep the audience interested. "These shows eventually do become boring and repetitive and, in time, the audiences will start to tail off. I fear that commissioners have painted themselves into something of a corner. There is a limit to how much the producers can up the ante, and on many of these shows we're close to that limit. Television has a habit of running with a genre and milking it dry. Throughout its history it has always managed to reinvent itself. "
But while there may be a limit to the audience's taste for punishing hapless members of the public with a misguided desire to be famous, their taste for humiliating down-on-their-luck pop stars, television presenters and glamour models appears to know no bounds. "Reality TV will definitely survive in celebrity formats," says the BB insider. "People will always like seeing things like Christopher Biggins trying to squeeze himself through a tiny hole."