Forget backstabbing, adultery and evil twins – the biggest drama for daytime soap operas is just trying to survive.

Once there were 19. Now there are four. And as Anthony Geary (Luke on “General Hospital”) admitted, “We’d been living on death row” before a recent reprieve for his show.

Which doesn’t mean that American viewers are done with soaps. Prime-time TV is starting to look a bit like the mid-1980s, when “Dallas,” “Dynasty,” “Knots Landing” and “Falcon Crest” ruled the ratings.

“I feel like ‘Revenge’ has really made soaps cool again,” said ABC Entertainment president Paul Lee.

That show marks a return to glitz and glamour – along with backstabbing, adultery and maybe even evil twins.

The list of daytime soaps has shrunk to two on CBS (“Young and the Restless,” “Bold and the Beautiful”) and one each on ABC (“General Hospital”) and NBC (“Days of Our Lives”).

“From the world of Luke and Laura’s wedding back in 1981, which was watched by 30 million people, the last 30 years have been the decline of the soap operas,” said Mark Rubinfeld, chairman of the sociology department at Westminster College.

That’s mostly thanks to changing demographics, as the housewives who once watched the shows while they did their ironing are mostly a thing of the past.

“Women went to work,” Rubinfeld said. “The stay-at-home-moms demographic, which used to be two-thirds of all women, is today somewhere between 25 and 30 percent.”

That’s why even the four remaining soaps aren’t exactly safe. Nancy Lee Grahn (Alexis on “GH”) compared soaps to “the walking dead” – and she wasn’t referring to the TV show by that title.

“We feel more secure,” says “Y&R” star Peter Bergman, because the shows that have replaced soaps haven’t drawn big audiences, but that doesn’t change the math. Daytime soaps are much more expensive to produce than talk/lifestyle shows.

“GH” producer Frank Valenti believes daytime soaps are “an original American art form” that has to adapt. His show has gone to shorter scenes and a faster storytelling pace.

But there’s a certain head-in-the-sand attitude that hasn’t disappeared. Jane Elliott (Tracy on “GH”) termed their unchanging nature “one of the blessings” of soaps.

“For 50 years, we have been telling stories five days a week, 52 weeks a year,” she said. “We are part of people’s milestones – when they are in a hospital with a sick parent, when the women are pregnant and they have their new babies and they come home. It’s not just people ironing.”

That’s ignoring numbers, however. “General Hospital” peaked at 11.4 million viewers in 1980-81. That number dropped to 2 million by 2011-12.

That’s quite a drop from the days of “Dallas,” a worldwide hit that drew 83 million viewers in this country when it was revealed who shot J.R. (Larry Hagman) in 1980. That’s 4 million more than the combined vote totals of Ronald Reagan and Jimmy Carter in that year’s election.

In the two decades since “Dallas” and “Dynasty” faded off the air, the vast majority of prime-time dramas and sitcoms have been serialized to one degree or another. Even crime dramas like the “CSIs” and the “NCISes” include ongoing personal storylines. And most TV comedies end their seasons with cliffhangers.

With fewer daytime soaps, TV screens are filled instead with “Real Housewives.” Viewers don’t need to invest five hours a week for months and years at a time to follow a reality show’s plot.

“It’s all about instant gratification, which you can get from reality TV,” Rubinfeld said. “And there are so many more choices. When Luke and Laura got married, there were only three, four, five TV channels you could watch. Now you have 500.

“On top of that, you have the Internet and all the social networking sites, so young women can get as much drama as they need from Facebook.”

This season, ABC added “Nashville” to “Revenge.” And you can certainly argue that “Grey’s Anatomy” and “Scandal” are just soaps of a different kind. The network will add “Mistresses” in 2013.

In January, NBC is debuting “Deception,” a soap/murder mystery. That’s when the revived “Dallas” launches Season 2 – or is that Season 16?

“There was a space open for this kind of show that was sort of missing,” said Gabriel Mann (Nolan on “Revenge”). “It had a retro feel to it.”

These days, “Downton Abbey,” the biggest pop-culture sensation to hit PBS in decades, is much like a prime-time soap set on an English manor.

Creator and writer Julian Fellowes said he patterned the show after American series, filling it with “big plots, little plots, funny plots, sad plots” because that “seems to be right for the energy of now.”

Oscar- and Emmy-winner Fellowes takes no offense when “Downton” is described as a soap. In contrast, Oscar-winner Callie Khouri (“Thelma and Louise”) makes it clear she doesn’t want her series, “Nashville,” placed in that category. “I’d rather call it a drama,” she said.

Which may explain why “Nashville” hasn’t caught the pop-culture comet the way “Revenge” has. It takes itself extremely seriously, whereas “Revenge” has fun.