Every year it’s the same, and every year it’s worse than ever. This year is surely the worst of all time, or at least since, I don’t know, 2007. Just look at the list of recent and coming movies, with all those darn numerals trailing after them: “Iron Man 2,” “Shrek 4” (whatever title DreamWorks Animation finally decided on), “Sex and the City 2,” “Toy Story 3.” Later on there will be a sequel to the audience-polarizing interspecies smackdown “Cats and Dogs” and a third installment (in 3-D, no less) in the “Step Up” dance franchise. And don’t forget “Twilight.” And “Nanny McPhee Returns.” And of course the next “Harry Potter” movie, which is coming in the fall.

Have the movie studios completely given up? Is originality extinct? It isn’t only the sequels that fuel such questions of course. (And the answer isn’t always no.) But the steady production of repeatable, renewable movie franchises provides both the clearest evidence of Hollywood’s fundamental cynicism, and also the best excuse to wax cynical about Hollywood.

Or does it? Of course it is absurd to deny that rampant sequelism is driven, above all, by commercial calculations. “Why did they make another Shrek movie?” one of my children asked me as we bought tickets to see it, and I suspect it was at least partly a rhetorical question. The first three made so much money that a fourth was pretty much automatic. Every few years since 2001, a new cohort of youngsters has arrived needing green ogre plush toys and other licensed Shrek merchandise to join their Buzz and Woody dolls and Spider-Man action figures.

The landscape is also littered with countless abandoned would-be franchises: “Narnia” appears to be getting a second chance, but it seems unlikely that “The Golden Compass” or “Cirque du Freak” or “Master and Commander” or the brand-new and struggling “Prince of Persia” will be so lucky.

All of these came from popular sources, which shows that success does not come automatically when best-selling novels or video games are adapted for the screen. Nevertheless, it sometimes seems that every commercially ambitious movie these days, with the possible exception of certain romantic comedies, comes with built-in sequel potential.

The mercenary impulses of the culture industry always have a plausible populist basis: DreamWorks Animation and Disney and Jerry Bruckheimer and Marvel Studios and all the other serial peddlers are giving us what we want — what they know we like. And this is hardly new. The current era of big-budget, mass-market movie sequelization dates back to the 1970s, when the personal cinema of the New Hollywood spawned, almost as a byproduct, a handful of nostalgic baby-boomer adventures, horror movies and action spectaculars that eventually took over the business.

Those of us who grew up in that era remember the unfolding of the “Rocky,” “Star Wars,” “Superman” and “Raiders of the Lost Ark” series, but it is easy to forget that movies like “Jaws,” “Carrie” and “The Exorcist” also spawned further episodes. And when you survey the much-maligned American cinema of the 1980s, it can be hard to find a popular movie that didn’t. There were “Lethal Weapon” and “Die Hard,” “Halloween” and “Friday the 13th,” “Batman” and “Rambo.” Remember all those “Police Academy” movies? Do you wish I hadn’t reminded you?

Sorry. Their persistence back there in the shadowy realms of collective memory testifies not only to the vexing ontological riddle that is Steve Guttenberg, but also — at least as profoundly — to a notable aspect of our deep human craving for narrative. Anyone who has told a child a bedtime story knows that its conclusion is met with the demand for “another one” — for the same one again, but a little bit different. Movies are far from the only medium to cater to this desire.

The current practice of presenting feature films as installments in a single story cycle recalls the old one- and two-reel serials that used to precede the main attraction in the pre-television era of movie-going. And it is hardly an accident that so many of the current franchises are spun from superhero comic books, which fed the youthful appetite of every generation since the Great Depression for open-ended storytelling.

Before that, there were crime novels and cowboy pulps. Back in the Victorian era there was Sherlock Holmes, a forerunner of both the 20th-century private eye and his superhero cousins. The great novels of Charles Dickens were first read in periodical cliffhanger installments. How far back should we go? Shakespeare’s continuing adventures of Prince (later King) Henry, that medieval muggle proto-Potter? It seems unlikely that Homer, whoever he was, recited the whole of the Odyssey in one sitting. Anyway, it was already a sequel to the Illiad, unless that poem was the prequel. And surely every little Greek kid wanted an Achilles action figure — Trojan horse sold separately.

To return to the modern world, there is television, a cosmos of narrative seriality in all its many shapes. There are, classically, the long and short arcs of the sitcom or the drama, the hour or half-hour that seems to occur in a vacuum, complete unto itself until the next week. There is the long, curlicued line of the soap opera, which has in the past few decades migrated from network daytime into prime time and then into the exalted realm of premium and basic cable. There are mini-series and spinoffs and, most recently and perhaps most radically, entire multi-season shows conceived as single, cyclical works.

One notable contrast, this year, between television and the movies is that a handful of TV shows actually and explicitly came to an end. “Lost” at last explained itself — or didn’t, depending on how you interpreted its conclusions; “24” ran out the clock; and “Law & Order” just stopped.

These different forms of closure and the popular reactions to them reveal various ways of dealing with loss. The ending of every story is an intimation and an allegory of death, which is one reason the cold finish of “The Sopranos” a few years ago felt so jarring and, upon reflection, so right. The slight disappointment with the last “Lost” was inevitable, since even a spiritual summation could not compensate for the rich, mysterious pleasures of the previous years. And the grief attending the demise of “Law & Order” was akin to that attending a death from old age. Yes, it was much too soon — it always is — but what a long, full life it had been.

Some of the most popular movie franchises of the past decade — the “Lord of the Rings” trilogy, the Harry Potter pictures and the “Twilight” saga — benefit from and are limited by built-in closure. All of them follow book series in which each volume is at once a satisfying, rounded-off story and the segment in a bigger, grander chronicle. Ideally, each of the films in these cycles should be able both to stand alone as a cinematic experience and flow into the whole. And in practice, at least for many legions of fans, they do.

But this is not so easy to accomplish with other types of story and other kinds of source material. The exhaustion of the superhero movie — I mean both the tiredness of individual films like “Spider-Man 3” and “X-Men: The Last Stand” and the general malaise afflicting this still-bankable genre — arises precisely from the difficulty of balancing the demands of seriality with the basic requirement of pleasing this audience at this movie right now. The teasers inserted into the first “Iron Man” to suggest delights to come in subsequent chapters felt ingenious and exciting. In “Iron Man 2” such forestalling and foreshadowing was annoying, as if we were being conned into future ticket purchases rather than given our money’s worth.

That is sometimes the fate of middle movies, though more often with superheroes it is Part 2 that stands out above the others. The dutiful expository business of explaining origins has been taken care of, and the hero can suffer, fight and explore the dilemmas of his dual nature. (This has been notably true of “The Dark Knight,” and the second “Spider-Man” and “X-Men” movies,) After that, things get too busy and baroque, and after the third or fourth installment the franchise fades away until the next reboot or casting change.

And then there are sequels that seem more like epilogues or redundancies — a category that includes “Shrek Forever After” and “Sex and the City 2.” The characters in those movies have already, in previous episodes, come to rest not in death but in its comic analogy, marriage. Of course, in real life, there is more to life than happily ever after, but it’s harder to complicate or undo that state in stories. Carrie and Big will no more be torn asunder than Shrek and Fiona, so the filmmakers have confected elaborately flimsy tales playing on the unconvincing possibility that they might. Shrek develops amnesia, Carrie a mild case of the two-year-itch, but the emotional investment is gone, and the stories have gone on too long.

Of the making of sequels, though, there will be no end. We all need something to look forward to. And something to complain about. I don’t know about you, but I can hardly wait until next summer.