In the 21st century, reality TV has turned into its own cottage industry — just look at the cast for the seventh season of "The Celebrity Apprentice," which premieres Sunday.

"Apprentice" head honcho Donald Trump has been firing people from his virtual boardroom for the past 11 years. But this season, his gaggle of boldfaced hopefuls is full of reality-TV vets. The cast includes Kate Gosselin of "Jon & Kate Plus 8" and, later, her own show; a pair of "Real Housewives"; and Lorenzo Lamas, whose resume even boasts a fake-ish reality show where he "played" himself ("The Joe Schmo Show," the Spike TV series where a single mark was surrounded by a cast of actors). Johnny Damon, the 2004 Red Sox hero, is a first-time reality-show castmember this time around, though he did appear on an episode of the fondant-minded series "Ace of Cakes."

Reality TV has become a big business for both broadcast and cable TV; next week across networks and cable, a slew of reality series will have their season premieres. Among the launches are three network titans — "Apprentice," the 14th season of "American Idol," and the 19th season of "The Bachelor."

At the same time, though, the genre might be showing signs of age — particularly on networks, where recent efforts to jump-start the genre have fizzled and schedule staples have run their course.

Fox's attempt to chronicle the birth and growth of a self-sustaining community "Utopia" made a splash when it premiered in September 2014, but the "social experiment" lasted less than two months — which, according to Bloomberg BusinessWeek, led to a loss in the $50 million range for the network and the show's producers. ABC's "Rising Star," a Josh Groban-hosted talent competition with an app tie-in that aired this summer, didn't bring in enough viewers to warrant a comeback. And Fox's "I Wanna Marry Harry," which added a royal twist to the "Joe Millionaire" concept of a rich guy not being what he seems, got the hook after four episodes.

Meanwhile, Gordon Ramsay decided that "Kitchen Nightmares," his restaurant rehab show, had run its course (though he's still sussing out new talent on "Hell's Kitchen" and "Master Chef"); and Simon Cowell's attempt to bring the British singing competition "The X Factor" to the States bottomed out after three seasons. And other longtime schedule stalwarts have either pared back or switched up their formats — "Idol," which has aired as many as three episodes a week in earlier seasons, will go down to a single episode per seven-day stretch this season, while "So You Think You Can Dance" announced a format change that will pit "stage" dancers against "street" dancers.

Initially, the appeal of reality TV was its relative cheapness compared to scripted programming that had to pay larger sums to actors and writers, although the big-budget failure of "Utopia" — where about 130 robotic cameras were stationed around the compound, and a complicated surveillance setup involved not just the TV show, but a website where the truly involved could peek in on the 15 cast members — shows how banking too much on one reality show can backfire. Before its ratings problems, the show was seen as potential glue for Fox's schedule — all that raw material could have been re-edited into new episodes easily. But not enough people wanted to watch what was already on TV.

Last month, the Los Angeles Times took a look at the decline of reality TV not just on networks, but on cable as well; among its evidence was TLC's shelving of "Here Comes Honey Boo Boo" after sex-abuse allegations came to light and ratings problems experienced by "Duck Dynasty," not to mention a general glut of shows that followed similar formats like makeovers or tattoos or "wacky" families. There are other signs of strain, too: The proliferation of nudity as a show's premise is a cheap eyeball grab made even cheaper by the requisite blurring of body parts. The producers of MTV's stalwart "The Real World" rankled purists when, early on, they forced the housemates to work together, but in recent seasons the show has engineered tension among its housemates by making uncomfortable situations its hook — "Skeletons," the pioneering show's 30th go-round, puts its cohabitating strangers in close contact with people who represent issues from their pre-TV past each week. And the bars on Jon Taffer's taproom-themed "Kitchen Nightmares" riff "Bar Rescue" are getting as much spotlight for their closures as they are for the makeovers that happened on camera.

Reality isn't going away; it's too irresistible to executives, because its relatively low prices and high churn are a bulwark against ad revenues' digital-era stagnation. But it might be in a place where it needs to radically reinvent itself — and not in a way that simply involves throwing a lot of money at a marketing campaign and hoping it sticks.

While it's true that the current pack of reality TV is led by a couple of shows that date back to the early 2000s, a couple of newer shows have captured viewers' imagination. Fox's "MasterChef Junior," which opens its third season on Tuesday, has delighted some because of its showcasing kids who are just really good at a useful life skill — and the notoriously screamy Ramsay's shift to a more gentle mode doesn't hurt. "Top Chef" continues to hum along, and reality shows like "Braxton Family Values" and "Love & Hip-Hop," while hewing to certain formulas, have allowed R&B artists to launch new albums into a marketplace in a way that sidesteps radio. And if nothing else, the "show a celebrity warts and all" reality subgenre gave viewers the Lisa Kudrow showcase "The Comeback," which just wrapped up its wrenchingly funny second season on HBO.

Perhaps the reinvention could boil down to one simple principle, inspired by the struggles "Utopia" and other go-for-broke shows experienced last year: Thinking small.

"While the age of Big Event Reality may be over, I don't think reality TV itself is on the decline," Boston-based TV writer Ryan McGee told the Globe via e-mail. "If anything, with the increasing number of TV channels coupled with Netflix, Hulu, Amazon, [and the like], the need for content is almost exponentially rising. Just as with scripted programs, reality will go niche, and still be appealing from an economic perspective from the companies that produce them and networks that air them."

And to viewers, too.

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Maura Johnston can be reached at maura.johnston@globe.com. Find her on Twitter @maura.