Coming not so shortly: a new helping of either Star Wars or Avatar for every Christmas between 2021 and 2027. Disney’s latest release schedule also promises eight more Marvel comic-book adaptations by 2022. Meanwhile, this year will see the spawn of not just behemoths such as Avengers, X-Men, Frozen, Toy Story, Spider-Man, The Lego Movie and Star Wars, but also less obvious franchise-launchers such as Godzilla, Men in Black, Shaun the Sheep, Angry Birds, Kingsman, Zombieland, Shaft and even Rambo. Never before have film sequels been so many and so varied.

They are nothing new, of course. The first specimen, The Fall of a Nation, released in 1916, followed the infamous 1915 Birth of a Nation. But in their early days, sequels were mainly cheap B-pictures churned out to reuse sets, costumes and props. Now, each new movie in a series grows bigger and costlier. The budget of the super-sequel currently hogging our screens, Avengers: Endgame, was $356m, compared with $220m for Avengers Assemble.

The industry’s eagerness to recycle is not hard to explain. As in the past, there can be cost savings, but revenue is a much bigger factor. Avengers: Endgame has become the fastest ever film to make $2bn, and has outstripped the lifetime take of the series original by more than $1bn. Of the all-time top 10 grossing films, six are now sequels – all released in the last four years.

New movies, old parts … Toy Story. Photograph: Sportsphoto Ltd/Allstar

More important than the scale of these earnings is their reliability. America’s highest grossing title ever (adjusted for inflation) is not a sequel: it is Gone with the Wind. Unfortunately, although an original hit may prove a bigger prize, nobody knows whether an untried property will succeed – however big its budget or stellar its talent. The success of a sequel is virtually guaranteed.

There are occasional misfires, like Solo: A Star Wars Story. But they are the exceptions to the rule. With its armoury of Star Wars hits alongside the bottomless Marvel treasure-trove and the soon-to-be augmented Avatar, the House of Mouse will be able to pursue its ambitious expansion plans with nary a qualm.

Just why sequels are so successful is no mystery either. They are less risky to make, because all involved know exactly what they are dealing with, and they also meet intense audience demand. Nothing whets filmgoers’ appetites like what the industry calls “preawareness”.

Huge and fanatical fanbases will keenly await each new instalment of an established franchise. Ordinary filmgoers may be less ardent, but plenty will still succumb to the allure of the familiar. Informed anticipation is part of the fun, and provides a ready topic of conversation. Audiences delight in well-recognised tropes, effects, settings, catchphrases and jokes. They develop a relationship with characters and actors.

Guaranteed hit … Batman v Superman: Dawn of Justice. Photograph: Clay Enos/AP

Cinema learned the potency of this phenomenon when television started stealing its audience in the 60s. Studios launched huge “event pictures”, but flops such as Cleopatra and Hello Dolly! brought them close to ruin. Then they discovered the fecundity of Jaws and Star Wars, and readjusted their strategy accordingly.

The resulting series were lapped up by newly enfranchised teenagers drawn to the burgeoning multiplexes of the 1980s. Since then – apart a brief fear of “franchise fatigue”, since proved unfounded – the sequel has never looked back. Avengers: Endgame reflects a further flowering of the process. By drawing on multiple existing series to deliver a further expansion, it is helping to build a “cinematic universe”. Man of Steel, Alien vs Predator and Fantastic Beasts are all initial steps towards the same process.

Sequels are set to get even mightier. Should we care? After all, some of them have undoubtedly outclassed their begetters. The Godfather Part II is often cited, as are The Empire Strikes Back, The Dark Knight and Terminator 2. Sequels allow characters to be developed, worlds to be expanded and stories to be refined. But the inheritor has a hard row to hoe. Often a story does not demand a second life, let alone a third, fourth or fifth. Creative exhaustion inevitably threatens.

Hence the resounding groan the subject of sequels so often inspires. There are plenty of gruesome examples to support it. Take your pick from Jaws: The Revenge, Scary Movie 5, Batman and Robin, Police Academy 7, Crocodile Dundee in Los Angeles, Superman IV, Blair Witch 2, Little Fockers, Transformers: Revenge of the Fallen, The Hangover Part III, Dumb and Dumber To, Sex and the City 2 and all too many others.

Outgunning the original … Terminator 2: Judgment Day. Photograph: Allstar/Cinetext/Tristar

Inevitably, the sequels juggernaut is throttling fresh ideas, the lifeblood of any creative activity. It may be offering the movies a short-term fix by imperilling their long-term health. In 2013, Steven Spielberg predicted that “mega-budget movies” would eventually crash, causing “an implosion”.

In the past, each excursion to the cinema unveiled a new world of characters, situations, stories, sets, locations and ways of seeing. Hollywood not only refreshed its own writers, directors, designers, actors and technicians, but also inspired the rest of us to look at the world afresh.

Now, such a service would perhaps be more useful than ever. Our world is in flux, and yet we are not encouraged to engage with change. Instead, we are offered the chance to retreat into thought bunkers with those of like mind, and cut ourselves off from unsettling ideas.

It is understandable that in such circumstances we should look to the big screen for the comfort of repetition. Children find it consoling to be told the same bedtime story every night. Maybe, however, it is time for filmgoers to grow up.