In what now seems the quaint era of Truman Capote’s baroque social diagrams, what distinguished the truly wealthy from the merely rich was the better vegetables they served: “tiny ones.”

Were Capote alive today to freeload off his social betters, the details he would most likely espy might not involve the fare at their tables — even the mega-rich do takeout — but the Hallstein water they import from Austria, or their $15,000 computer-operated Danish TopBrewer coffee systems, or the $700 hand-embroidered monogrammed towel sets they order from the cult Florentine linen shop Loretta Caponi, or even the subtle toggles they use to switch off a light.

Lately throughout gentrified Brooklyn — or Hollywood on Hudson, as some call a borough now home to Adam Driver, Matt Damon, Michelle Williams, and Daniel Craig and Rachel Weisz — the brownstone superrich signal domestic chic with decorative details like a $220 light switch manufactured by the English company Forbes & Lomax.

For the average home renovator, of course, a $22 Leviton light switch from Home Depot does the job just fine. Yet no five-story Brooklyn Heights behemoth, where the obligatory uncurtained windows open up on scenes reminiscent of ethnological dioramas (Exhibit A: Lives of the 21st-Century Technocrats), can be considered complete anymore without Forbes & Lomax toggles in each room.

Or they are a domestic version of Kendall Roy’s Loro Piana baseball cap in “Succession” (remember “Succession”?): absurdly costly, yet so subtle you only notice them if you already know how expensive they are?

“Nothing should be noticed” is a dictum often attributed to the heiress Bunny Mellon. In truth, the reverse was improbably the case. It was in Mellon’s ostentatiously modest habit of ordering haute couture garden aprons from Givenchy and hanging her best Braque in a basket room that one could detect early groundwork being laid for what would eventually be marketed as “quiet luxury,” according to the Mellon biographer Mac Griswold. “That sort of ‘What me — rich?’ attitude originates with her,” Ms. Griswold said.

For Old Money like Mellon’s, discretion was indeed a key value, while for those in the class of New Old Money — that is, great fortunes made, often in tech, in a time frame bracketed by Myspace and TikTok — wealth display is noticeable, but only to those who know what they’re looking for.

And, as trends go, “stealth wealth” was one well suited to a moment in which social media has made us all into de facto voyeurs, noses pressed to the digital window as the grotesquely wealthy flaunt their toys, their cars, their designer fashions, the closets in their 35,000-square-foot Calabasas mansions devoted to Hermès Birkin bags. “We are collectively spending more time checking out what the rich and famous are doing and less time on what Barry from H.R. and Sandra from accounting were up to last weekend,” said Nicholas Bloom, the William D. Eberle professor of economics at Stanford.

We are parsing Veblenesque narratives laid out for us by glossy strangers, people like the supermodel and philanthropist Karlie Kloss, who happens to be married to Josh Kushner — an investor whose stake in onetime start-ups like Instagram, Spotify and Slack yielded a personal fortune estimated at $3.6 billion.

In posts created for the delectation of her 12 million Instagram followers, Ms. Kloss conjures a narrative in which she and her family inhabit a digital empyrean, someplace universes away from the paycheck-to-paycheck worries of hoi polloi. In Kushner-Kloss world, the light is always honeyed, air travel quietly private and human and divine seemingly will converge somewhere in the Grenadines aboard the poop deck of the billionaire David Geffen’s humongous Lürssen yacht, Rising Sun.

“Wealth porn,” Stellene Volandes, editor in chief of Town & Country, termed such postings. And as with any permutation of adult entertainment, it’s free online: Anyone can watch.

Things were not always thus. Back in the remote Reagan ’80s, also an era of unbridled wealth creation, opulent status display may have been occasionally grotesque (think birthday parties for 500 in the Metropolitan Museum of Art’s Temple of Dendur), and yet they were far less visible to the general public. Hedge fund moguls, predacious leveraged-buyout kings and real estate tycoons competed shamelessly to out-party, out-dress and out-spend one another, mounting lavish entertainments for “Champagne-swilling, caviar-supping, Lacroix-wearing” guests, as The New York Times once noted. Yet their excesses were noted by a relative few.

“In the ’80s, you could give a private party in a public venue like the Met, wear Lacroix poufs, have Robert Isabell design a one-night-only Versailles décor for you, flying in all the flowers in Holland,” Mr. Norwich said. “And the only risk to your privacy was maybe a few media outlets hovering outside with a pen and pad.”

Showiness of that kind is not only frowned upon in the age of New Old Money. It risks courting the dangers common to countries where the greatly wealthy are obliged to live heavily guarded and sequestered lives. “You don’t want to become a target,” Mr. Norwich added. Hence in recent years, the offspring of plutocrats — the billionaire Mort Zuckerman’s teen daughter for example — find themselves chauffeured to drop-off at elite private schools in S.U.V.s replete with tinted windows and attendant security detail. “Those ’80s excesses could not have happened if everyone had an iPhone,” Mr. Norwich said.

Privacy, discretion and to a large extent anonymity are the baseline for stealth wealth. The quiet luxury trope developed to conceal the unvarying truth that the essential status marker is “how much space you take up,” as Mr. Norwich said.

He meant economic space. And in that respect, Americans dominate the world, the superrich here making up more than a third of the global population of ultrahigh net-worth individuals (UHNWI), according to a Wealth Report issued by Knight Frank, an independent real estate consultancy that has its headquarters in London. It is that group, far more than the “1 percent” (a club whose entry point is a mere $30 million in net worth) that increasingly comes to define a new world order at the upper echelons of income.

Not surprisingly, that UHNWI group also occupies space in a literal sense, given that between them, the 13 largest individual landowners in the country — think John C. Malone, the owner of Liberty Media and the Atlanta Braves; Ted Turner; or Peter Buck, the Subway co-founder — control over 16.9 million acres of land in the contiguous 48 states, an area equivalent to the size of West Virginia.