Now that “Blair Witch,” the abysmal shaky-cam horror sequel that no one was waiting for, has come and bombed, you might be tempted to say that a certain genre is ready to lay down and die. But you’d be wrong. In the megaplex, of course, the found-footage horror film enjoyed a quick rise, a brief reign, and (now) a spectacular fall. It was launched, in 1999, with “The Blair Witch Project,” which in addition to being a highly original and — yes — unsettling movie became a fascinating phenomenon in two ways. First off, its success was beyond staggering, and not just because its $140 million domestic gross gave it the greatest budget-to-profit ratio of any movie ever made. Budget aside, “The Blair Witch Project” put more butts in seats than “Pulp Fiction” did. Clearly, that had something to do with the dread and intrigue generated by the uniquely austere thriller up onscreen, and everything that people said about it. It triumphed because it was truly a movie to see.

Yet the second way that “The Blair Witch Project” was a fascinating phenom is that it quickly became the most reviled big-hit indie movie of all time. As in: If I had a nickel for every person who saw “The Blair Witch Project” and wanted to tar and feather the projectionist…

Many loved it; a great many hated it. That can happen, of course, but there was a singular and notable line-in-the-sand quality to the reaction that swirled around and against “The Blair Witch Project.” You might say that it was the first blue-state-vs.-red-state indie movie (I mean that metaphorically rather than in any literal political way), the quirk being that the members of both states were seated right next to each other. The blue staters saw a tense and tingly nightmare that unfolded not just in the usual darkness but in genuine godforsaken night, with a cackling revelation — the spectre of the witch — always waiting just around the corner. The red staters saw a movie that was all foreplay and no climax, with endless tedious handheld camerawork, a threadbare ramble that devolved into a murky technological tease.

Seventeen years later, I’m tempted to say that both sides were right. I loved “The Blair Witch Project” the first time I saw it — I was swept up in its look, its mood, its night-bloom existential terror — but even as a fan, I admit it’s not a horror film you can really go back to the way you can to “Psycho” or “Carrie” or “The Texas Chain Saw Massacre” or “Audition,” to revel in its scary glory a second time. It’s an extraordinary stunt, one that’s meant to be consumed — perhaps — just one time only. That’s okay; some movies are like that. But it’s been the peculiar destiny of “The Blair Witch Project” to be the most influential horror film since “The Texas Chain Saw Massacre.” It was that 1974 classic that spawned the slasher genre. (Yes, there were other influences, going back to “Psycho,” but Michael Myers in “Halloween” was simply Leatherface with a suburban makeover.) Likewise, “Blair Witch” revolutionized the found-footage genre for the digital-recorder era. The paradox — a poetically perfect one — is that it’s a genre that was spawned, and has largely remained, underground.

It really started, of course, in 1980, with “Cannibal Holocaust,” the deservedly infamous Italian shocker that was banned in several countries, in part because some people thought it was real. In one way, it was: No human beings were killed during the making of the movie, but some animals were, and that crossed a line that should never have been crossed, one that helped to lend the entire film its murderous edge.

The reality factor of “Cannibal Holocaust” was, in its way, a deliberate extension of the mood struck by the opening title of “Chain Saw,” with its implication that the story it was about had actually happened. In “Cannibal Holocaust,” we aren’t just watching a wormy gruesome exploitation horror movie about a film crew that burrows into the Amazon rain forest in 1979 to shoot a documentary about tribes that practice cannibalism. We’re watching the raw footage they shot of their expedition, which places a disquieting frame of reality around the most hideous acts of violence. In horror, the this is really happening! era had begun, a form and mood that was at once genuinely artful and worthy of P.T. Barnum.

“Cannibal Holocaust” is a cult film that never lost its glow of danger because it remained, for most moviegoers, under the radar. It took 19 years for “The Blair Witch Project” to drag the found-footage concept into the light, and though the movie created what is arguably the most virulent backlash in the history of cinema, once the form got pushed out there, it spread and mutated, and mainstream audiences had a shivery love affair with it, though it was a while before the relationship took hold.

“Cloverfield,” the first found-footage hit after “Blair Witch,” didn’t come out until eight years later. It was basically a grabby artless gimmick, a Godzilla movie in glossy concocted found-footage drag, which now had the semi-official imprimatur of being a “millennial” form. The first two questions on any film executive’s mind — is there an audience? And what is the audience? — could now be comfortably answered by any film executive’s proverbial favorite answer: The kids will eat it up! And they did, though whether or not they actually liked it is another story. As a movie, “Cloverfield” was flashy and consumable and not all that good for you, like a fast-food binge.

The genre might have headed for oblivion were it not for the little film that jump-started it, reinvented it, and actually improved it. Seven years ago this week, “Paranormal Activity” upped the ante on the whole found-footage thing by taking it out of the streets and placing it in the suburban bedroom (and — thank God — locking down the hand-held camera). The movie, and its surprisingly good sequels, reconfigured the history of the haunted-house thriller by feeding it through the snap, crackle, and electromagnetic pop of 21st-century surveillance technology. We’ve had one “Paranormal Activity” movie every year since (except for 2013 — they must have figured that would be bad luck). And though there’s none scheduled for this year, perhaps we can count Olivier Assayas’ upcoming “Personal Shopper,” a sleek but terrifyingly oblique ghost story, starring Kristen Stewart, that I have already dubbed “Paranormal Inactivity.” (Forget the malls; I’m not even sure this one will levitate in art houses.)

The “Paranormal Activity” films, coming like clockwork once a year at Halloween, absorbed all the mainstream found-footage mojo. They soaked up and wrung out the genre, to the point that “Blair Witch,” this weekend, became the ultimate too-little-too-late sequel. Of course, it didn’t help that the movie was as bad as it gets. It had nothing new up its tattered video sleeve, and zero fear factor. It was also the last nail in the coffin for two aspects of the form. The handheld camera? This movie would make you sick from it even if you don’t get vertigo. Sick from the pointless wavery monotony, and from the infamous elephant in the room that’s been hanging over the genre ever since “The Blair Witch Project” — namely, who the hell is still holding the camera, and why? At one point in “Blair Witch,” a freaked-out character climbs a pine tree, branch upon branch, and the notion that a camera is still somehow recording her movements crosses over from the absurd to the insane.

The other genre-killer is, of course, the bad acting. The 17 years since “The Blair Witch Project” have overlapped almost exactly with of the age of reality TV, a period in which audiences have become highly accustomed to deconstructing layers of staged “authenticity.” In found-footage movies, there’s almost always a gaping disconnect between the alleged spooky rawness of the style and the image of lousy good-looking young actors trying to convince us that they’re “actual people” by doing that odd thing of overacting their underacting. “Look, everybody! This is a real home movie! And I’m just, like, another dude named Jason!” Yes, dude, you are. Another mediocre actor named Jason who can’t fool us for a second.

It sounds like I’m writing an epitaph for the genre. Except for one thing: Despite the fade-out of its two reigning franchises, the genre is far from dead — in many ways, it’s thriving. You just have to look under the carpet, or maybe under a rock, to see that it’s still a wriggling life form. It has the potential to blow the minds of mainstream audiences all over again, the moment that a really smart filmmaker — and I guarantee you this will happen — figures out how to lift it to the next level.

A lot of moviegoers — most — wouldn’t know it, but a bit off the beaten path, we’re still in the early high renaissance era of found-footage horror. In the demimonde of creepy low-budget independent cinema, we’ve had found-footage zombie horror (starting with “[REC]” and culminating in George Romero’s little-seen “Diary of the Dead”), found-footage outer-space horror (“Europa Report,” “Apollo 18”), the cyber-found-footage movie (“The Den,” “Unfriended,” “Nightmare Code”), the found-footage demonic-possession film (“The Last Exorcism,” “The Devil Inside,” the is-it-Alzheimer’s-or-Satan? “The Taking of Deborah Logan”), the post-“Cloverfield” found-footage Norwegian giant-monster movie (“Trollhunter”), the found-footage doomsday-cult nightmare movie (“Apocalyptic,” “The Sacrament)”, the found-footage serial-killer meta-thriller (“The Last Horror Movie”), not to mention oddballs like the psychotic found-footage ghoulfest “Grave Encounters.”

The reason these movies, and dozens I haven’t mentioned, even exist is that all the original elements that fused into found-footage horror aren’t going away. The omnipresence of technology, coupled with our increasing compulsion to document every aspect of our lives. The idea that all those personal images are recordings that conceal as much as they reveal. And, of course, the belief, embedded deep in our central nervous systems, that ghosts and monsters really exist, and that they will always find new ways to frighten us, from the moment the old ways are used up. The deep reality of found-footage horror is that it’s such a pure extension of the movies themselves: a way to reveal that the beast is out there, that he’s not just part of some cornball scare story, and that if you just look close enough, that if you look right into the film, you’ll really, truly see him.