Bad news, ladies: the Geezer Roué—the dashing older (and much older) playboy who saw New York as the verdant playing field of seduction; that dignified and slightly sleazy social genus (and genius) who bloomed in New York City like some rank but irresistible flower, spreading sulfurous spores through the open windows of young women’s studio apartments—is no more.

“That breed is almost extinct,” offered pop culture sage and Vanity Fair columnist George Wayne. “Thank God for Jack, and his sagging scrotum sac, for still holding the fort.”

“Jack” being Nicholson, of course, who last month was famously photographed on a boat off the coast of France, shirtless and pork-bellied, licking his lips before moving in on a foot-long sub. Looking at the photograph of the actor, who turned 70 this year, one realized: Here is the last truly happy man on this overly analyzed, politically correct, downward-dogging, grass-fed, girls-gone-wild planet. His belly said it all: I came, I saw, I conquered.

Burp.

Mr. Nicholson comes at the end of a long and distinguished Hollywood lineage of Geezer Roués: Douglas Fairbanks Jr., David Niven, Rex Harrison, Robert Evans, Darryl Zanuck, Alan Jay Lerner, Jimmy Van Heusen. On this coast you had Bill Paley, Nelson Rockefeller, Huntington Hartford, Taki Theodoracopulos, even The New Yorker’s Brendan Gill. (This was a time, dear young’uns, when male literary lads ran barefoot through the typing pool rather than setting up house in a comfy Brooklyn brownstone.) Mr. Nicholson’s compatriot roués—Warren Beatty, Michael Douglas—have been tamed, to some extent, by much younger wives and the recognition that perhaps it’s better to go gently into that saggy night. If you want to see a Geezer Roué manqué, have a look at deflated Bill Clinton as he plays the Good Boy on his wife’s campaign trail.

Not so long ago, it was not uncommon to encounter silver-haired womanizers, stinking of Bay Rum, wolfishly a-prowl in Manhattan. What distinguishes the roué has always been his impeccable manners—wealth and success, to be sure—and more importantly, the sense of artistry with which he approaches his life’s ambition: to love and be loved by women. It was less about sex and more about sensibility. Especially if that sensibility had great legs and was significantly south of 30.

But a moment of silence, please: the bell tolls for the Geezer Roué.

Rarely if ever anymore do you see that nattily clad, well-tanned if slightly creepy gentleman leaned up against the end of the bar. Theories abound as to what confluence of conditions has this once proud beast limping toward extinction.

“The art is dead—so are they, for the most part,” said James Lipton, host of Inside the Actors Studio, one night recently at Elaine’s as he took tiny sips of Calvados. Mr. Lipton bemoaned the fact that there are so few roués—and he’s observed many over the years—left for him to put on the hot seat on his TV show.

“Warren Beatty was a successful roué,” he said. “He lived at the Beverly Wilshire Hotel. I remember when Shirley McLaine was on my show, saying, ‘Have you ever had Warren on your show?’ I said, ‘No.’ She said, ‘He’s got to do this show. Oh, God, the stories he could tell.’ Later, she said to me, ‘I just would love to jump his bones, just to see what all the shouting’s about.’” (Note to the younger reader: Ms. McLaine is Mr. Beatty’s sister; she was clearly joking. However, that’s the kind of hold the roués once held on all femaledom.)

Mr. Lipton sipped some more Calvados. “The amazing thing about a genuine roué,” he said, “is that women know that you’re a roué. Which is to say that infidelity is in the cards. That whatever you’re going to do with them, or to them—or for them—is purely temporary. You’re not going to be there in a few months. Otherwise you’re not a roué. And yet, they succumb to the roués. That’s the great art of roué-ism: Despite the fact that they know you’re a son of a bitch, and it’s all going to end badly for them, nevertheless they take the plunge.”

But the pool in which to plunge is leaking water fast.

“I think the buzz-kill that came in is called the healthy lifestyle,” said New York artist Peter Tunney, who was a budding roué until he walked the aisle this spring at age 45. “There’s a big vibe out there to do everything right. You have to get home on time, you have to get up early, you have to run in the morning. You have to eat green grass for breakfast.”

For 10 years, Mr. Tunney shared an art gallery with photographer and roué Peter Beard.

“Listen, there’s two parts of this,” said Mr. Tunney of roué-ism. “One part is, you love women. That’s just the truth of it. That’s what all these guys have in common, they really love women. And they’re not willing to just settle down. They love their life, they love entertaining with women, they love traveling with women, they love being with them and they love their company and everything else.

“So you have women—and then you’ve got drink. But it’s excess that ends up being the drag. When you’ve got too much excess going on, you really start to become an idiot. And the quality of the people goes down after a while: Who’s there at 7 a.m.?”

Mr. Tunney, who is sober these days, insists that life still has an edge. He still enjoys a large plate of eggs in the morning and he has a brand-new scooter.

“I‘m much happier now and much humbler,” he said. “So paradise lost for me is paradise found.”

But the Vespa-and-eggs technique hasn’t worked out for everyone. The writer and roué Anthony Haden-Guest has moved to London and is no great hurry to return.

“The massive streak of Puritanism in America has reasserted itself, especially amongst liberals,” he said, adding that New York is no long the racy place it was in the 70’s and 80’s. “When I moved to New York there were still a bunch of good writers, often half-drunk, but still very good writers. That doesn’t exist anymore. Where do they go? They probably go and teach at Bard. All the roués I know are reformed or gone back to Europe.” (Like all good roués, Mr. Haden-Guest takes exception to being labeled a roué: “I work extremely hard and have a little fun sometimes.”)

The Actor Studios Mr. Lipton theorized that the young women whom roués would typically prey on have become so sexually liberated and media-savvy that such a plunge today has all the mystery and danger of jumping in a puddle in your rain boots.

“That was part of the allure of the roué; he was something dangerous,” said Mr. Lipton. “He lived in the shadows. And the woman who got involved with the roué knew she was skating on thin ice. There was that excitement.” He noted that women would often get involved with these old devils to boost their visibility.

But in the post-Paris-Hilton-sex-tape era, succumbing to the charms of an older man is not going to raise eyebrows. If a young woman wants to be noticed skating on thin ice today, she simply removes her underwear, clutches her ankles, puts her trust in zoom lenses and glides.

“The wages of sin are pretty damn good,” said Mr. Lipton. “Where does that leave the roués? Somewhere out on the fringes, desperate to attract some attention. It’s not glamorous and sexy. It’s tame compared to these kids running around in their underpants.”

Indeed, some roués have started committing the No. 1 roué sin—boasting. A whiff of desperation accompanies an upcoming article in GQ magazine in which 57-year-old Virgin Atlantic billionaire Richard Branson brags about how he became a member of the mile-high club.

“We got chatting and it went a bit further. And it was every man’s dream, to be honest. I was about 19,” the flaxen-haired honcho is quoted as saying. “What I remember vividly is seeing four handprints on the mirror as we finished, and thinking I’d better wipe them off.”

Mr. Branson—who is married but famously surrounds himself with beautiful young women—surely knows better than to wrap his rascal in what looks an awful lot like a sales pitch.

The roués are mourned not only by the women who succumbed to them; the fact was, a roué was damned good company even if—maybe especially if—both parties remained fully clothed.

Elaine’s habitué Ruda B. Dauphin, the American representative of the Deauville Film Festival, said she had the pleasure of knowing a number of roués in her day. There was the great choreographer Serge Lifar. “Oh, I loved him,” she said. “I wanted to have dinner with him and talk to him and flirt. Who flirts anymore?”

Ms. Dauphin added that greed has unfortunately replaced lust as the deadly sin most in evidence.

“Everybody’s greedy, everybody wants to make money, everyone wants to buy things,” she said. “You wanna buy a yacht, an apartment. How much time have you got to spend seducing women or men? And it’s a pity, because it’s much more provocative to spend time seducing friends, lovers, possibilities, the girl next door, the boy next door. Come on. Come into my web. Be a spider.”

“That Rat Pack sort of style would seem ridiculous today,” said Shawn Levy, author of The Last Playboy: The High Life of Porfirio Rubirosa, a biography of the polo playing, Ferrari-racing Dominican playboy who married five times, including the likes of Barbara Hutton and Doris Duke, and died in a car wreck at age 56. “In that era when old folks had center stage in pop culture, they could sort of set the socials standards, the sartorial standards, the rules of mating,” said Mr. Levy. “But as soon as the kids took over, then any adult that tried to hit on a woman by acting young looked foolish. The only guy who can get away with it today is George Clooney. You have to have a great amount of not-give-a-fuck-ness. You can’t do this if you’re worried about how you look.”

Nor if you’re overly worried about your health: The empowerment of young women—to be as bad as they want to be, to enjoy sex as much as they want to—has perhaps raised the stakes of the game too high for many a geezer heart to bear.

“Roués are now terrified that they’re going to come after a woman and the woman will just scare the daylights out of them,” said advertising executive Jerry Della Femina, at a recent party he hosted at his East Hampton home.

“You have to understand that these days it’s looked down upon to be a sensualist,” said society photographer Patrick McMullan, 51. “And although I started my career so I could have a drink in one hand and a camera in the other, it’s sort of frowned upon to be not serious.”

(Mr. McMullan said he considers himself a roué enabler, because when he takes pictures of young women with older men, “the young girls realize, ‘Well, my picture is being taken, so if I hang out with this guy, maybe I have to put out a little, but I’ll get some attention, too.’”)

“The whole roué dynamic changed when Warren Beatty decided to settle down with one woman and spawn like what, 20 kids,” said Vanity Fair’s Mr. Wayne. “He knocked up that poor woman into oblivion, ruining Annette Bening’s brilliant acting career in the process—which I suppose is the ultimate revenge for the roué.

“There are hardly any leading men in Hollywood today who fit that mold,” he continued. “Brad Pitt has been hen-pecked into creating his own mini United Nations.”

Meanwhile, Mr. Levy was wondering if our sub-sandwich-scarfing Ur-Geezer Roué could still pull it off: “I think if Jack Nicholson walked into an L.A. nightclub, most of the young girls would be scared.”