This may come as a surprise to Channel 4, which has just secured the UK rights to The Simpsons for £1m a show, but the most popular TV programme in the world could be on its last legs. Not that Matt Groening, the show's genial creator, who was in Bristol last weekend to open the Animated Encounters festival, puts it quite like that.
However, he's the first to admit that "it becomes increasingly difficult as the years go by to keep on not only surprising the audience, but surprising ourselves".
When The Simpsons was first put out as a stand-alone series in 1989 it attracted a great deal of criticism in the US, particularly from the Christian right. But the show has now become so popular that it usually stays out of trouble, says Groening. For instance, no one wrote in to complain when, in one show, Homer smoked cannabis to relieve his pain.
Now on its 13th series, playing to more than 60m people in 60 countries - exceeding even Baywatch in its prime - the Simpsons have become global icons. The power of the brand is such that Brazilian tourism officials were up in arms over a recent episode showing the family visiting Rio de Janeiro, where they were kidnapped, robbed and attacked by monkeys.
But while Groening, a middle-aged, bearded character, seems almost bemused by the programme's success, he senses that its days may be numbered.
"I think we are closer to winding it up," he says. "Although what happens generally if we win the Emmy for best animation show is that that gives us another couple of years to run it into the ground."
Fox, the Rupert Murdoch-owned channel which has shown The Simpsons for the past 13 years - and is said to have made more than $1bn out of it - would be happy to continue forever, he says. "I think Fox will wring every last penny out of the show before they call it a day."
The relationship between Groening and his paymasters has been a textbook case study of artist-manager conflict. "I have made them billions of dollars, so there is a trace of a smile in their faces when I walk into the room," he says.
But Groening is unhappy about Fox's handling of Futurama, his animated science fiction show. Now in its fourth series, Futurama is Groening's comic vision of the future, which owes much visually to The Simpsons, but is a very different kettle of fish.
While Fox is showing this season of the series, it has refused to order another, blaming slipping ratings.
The Simpsons was always going to be a hard act to follow; Groening says he feels like Paul McCartney after the break-up of the Beatles. But as far as he is concerned, the problem with Futurama is that Fox doesn't understand it.
"They haven't really supported it. I think it's a worthy companion to The Simpsons and we're really proud of it. But Fox gave it a bad slot and zero promotion for the last three years."
Critical interference has been another, intermittent problem. "I was getting notes from them which contradicted themselves. The show was getting further away from what I wanted to do," he says. "They would write notes like: 'These characters are too mean.' I thought, you could say that about the Simpsons, but if they had been nice we wouldn't be talking today."
However, he is determined to prove Fox wrong about Futurama, and he is not alone in his campaign for the programme. An internet petition - not organised by Groening - has already collected 105,000 signatures of fans who want to save the series.
If Futurama is dumped, Groening has several other ideas in development. He describes them as "similar" in design to The Simpsons and Futurama. The characters will look like relatives of those characters with the classic "mouth overbites".
Given how important The Simpsons is to the network, couldn't Groening threaten to break away from Fox unless they show Futurama? "That really wouldn't be my style," he says.
No doubt the outcry would be even larger if The Simpsons was to be canned. But while Groening suggests declining inspiration for the programme, he still has a few ideas.
One of the most obvious themes of the show is that people in authority do not always have the best motives. And that, too, applies to big business.
Groening is set to poke fun at Enron and Anderson in his next series, while Krusty the Clown will run for Congress with the endorsement of several real-life politicians.
"The fact is that there is a lot of fast food out there and shoddy toys and your newspaper is full of stories about the people who provide this stuff."
Although this is a tad rich coming from the man who spawned tens of thousands of Simpsons paraphernalia including T-shirts, tea towels and bubble bath, the anti-establishment streak in Groening seems to spur him on.
"I think there is a lot of corporate irresponsibility. Consumers are bombarded with commercials and hype and propaganda and I think it's healthy to provide a counter-message," he says.
But despite such ideas, there is a sense that he has become increasingly detached from the creative process. He has a team of 20 writers putting together The Simpsons and he says his suggestions often get over-ruled.
Having to manage his own production company - it makes Futurama but not The Simpsons - which has about 50 employees, including animators and post-production staff, also may have affected the level of involvement in The Simpsons.
"I wear two hats," he admits. "One is as the cranky cartoonist, but I also have to worry about a lot of people and be a manager and boost morale and all that stuff. I'm not particularly fond of the stuff which takes me away from the creative side."
For several years, there has been talk of a Simpsons film. Many fans think the programme could make the leap to the big screen, just as South Park did.
As far as Groening is concerned, however, it is not clear whether Fox wants it or not. Creating a 30-minute programme is very different from making a 90-minute film, and he is wary that a poor movie could affect the television show.
He is concerned about "jumping the shark", a phrase which refers to that defining moment when a TV programme has reached its peak. The phrase comes from a 1977 episode of US sitcom Happy Days, in which its main character, the Fonz, ditches his motorcycle for water skis and attempts to jump over a shark - after that, the legend goes, the show ceased to be funny.
But Groening is also pragmatic about the show's shelf-life. "Because animation is such an intensely painstaking process, it wears people out, and audiences are always looking for surprises. When any character is as stupid as Homer Simpson, it's hard to keep surprising the audience."