The most profound recent development in men’s clothing concerns the millimetric adjustment of a garment first sold in 1900. In January, Brooks Brothers issued a redesign of its oxford-cloth button-down, the shirt known commonly, and not quite insufferably, as an OCBD.

The upgrade to mother-of-pearl buttons, the addition of side gussets to the shirttails, even the disappearance of the breast pocket — these tweaks are no big deal, unless you are an emeritus professor wondering where now to stick your reading glasses. The removal of the collar’s interior lining, however, constitutes a major moment in the history of minutiae, as it reinstates a first-rate collar roll.

With its points buttoned down, the unlined collar spreads and bends at its front edges to form an elegant bell curve, or maybe to slither a bit asymmetrically — a casually dashing soft contour among the strict lines of traditional men’s wear.

This is the sort of detail in which God is said to exist. Philosophers of the Ivy League Look liken particularly dramatic collar rolls to the silhouettes of angels’ wings.

In 1896, John E. Brooks admired the hidden buttons that secured the collars of English polo players and began engineering his sportswear classic, with its incidentally spiffy arc to the collar.

“The distinctive roll was prized for its nonchalance going back to the 1920s,” said Christian Chensvold, the founder and editor in chief of the trad-fashion website Ivy Style. That Mr. Chensvold broke traffic records with his coverage of the new button-down suggests the peculiar gravity of the quintessential American clothier’s reworking of its quintessential product.

It also indicates the richly complicated feelings of Brooks Brothers’ most passionate customers, who double as its least patient critics, vexed that its emergence as a global brand complicates sober stewardship of its establishment legacy. “For basic men’s wear, Brooks Brothers is the source; it’s the prehistoric mud,” said Lisa Birnbach, editor of “The Official Preppy Handbook” and a co-author of “True Prep.” “Because of that, people get very proprietary.”

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Mr. Chensvold said, “What they did with this shirt is symbolic of what’s going wrong with the whole company.”

Oh, he appreciates the new shirt, which he bought at the Madison Avenue flagship store, where he is a regular, he said. But he would have appreciated the company’s acknowledgment that it had grievously erred when it added the lining around 1989. “There was no mea culpa,” he said, adding: “Don’t make me sound too censorious. I’m always afraid they’ll take away my third-floor golf-simulator privileges.”

According to Guy Voglino, the Brooks Brothers vice president charged with managing men’s wear, the company decided that its oxford-cloth button-down “needed to be refreshed” last year. “We looked back and softened it up,” he said.

The reference points were the button-downs of the 1940s and ’50s, when the Brooks Brothers shirt was firmly established as a crucial element of insouciant collegiate style, the more frayed the better. In his memoir, “Out of Place,” Edward Said wrote of watching two Princeton classmates apply “sandpaper to a pair of new blue button-down shirts, trying in a matter of minutes to produce the effect of the worn-out aristocratic shirt.”

After pausing to note that Brooks Brothers’ return to tradition has involved discontinuing the “traditional fit” button-down — the baggiest cut, sized to skim the torso of Ray Bolger’s Tin Man — we see that the company is reaping considerable rewards by re-engaging with this heritage. “We are probably selling 15 to 20 percent more units,” Mr. Voglino said.

Some who expressed mixed feelings about the throwback shirt included hard-core traditionalists: men who embrace sack suits and rep ties as a shelter from the shifting winds of fashion, people harboring informed opinions about the collar rolls worn by William F. Buckley on “Firing Line” and Miles Davis on the cover of “Milestones,” holdouts disdainful of Uniqlo’s of-the-moment oxford, with its paltry button-down collar.

The cost of the Brooks Brothers shirt — $140, from $92 — is their chief complaint: A shirt often treated as a workhorse is now valued like a thoroughbred, which is particularly scandalous to members of a sartorial subculture that makes a virtue of frugality, accruing social capital by finding Cordovan loafers at thrift stores.

On the other hand, a certain resentment of the merchants on which they rely (a state of perpetual laments that things aren’t as good as they used to be) seems to be a feature of the new trad worldview.

And the ready availability of the old-is-new shirt saves a lot of trouble for collar-roll connoisseurs who have been relying for decades on tiny mail-order shops with long waiting lists or troubling tailors to move their collar-point buttons by an eighth of an inch. It’s both lovely and risible at once, all this fussing over a collar prized for its unfussy appearance. “Nonchalance is everything to a preppy,” Ms. Birnbach said. “It’s a virtue, a value, a trope and an aesthetic. As far as studied nonchalance is concerned, that’s how you learn.”