Céline is the fashion brand named by Vogue as “achingly cool.” It’s the label where “all the season’s trends are born,” the magazine wrote in January. This year Céline chose Joan Didion to be the face of its spring line. Didion, whose two most recent books are about death and mourning, is 80. The subliminal message of the ad campaign is obvious: eat it, youth.

Youth is no longer cool—or at least its hold on cool has weakened. How did that happen? Perhaps we can trace it back to 2012, when American Apparel, a brand that typically prefers a barely legal aesthetic, chose as its new face Jacky O’Shaughnessy, an “advanced” model in her 60s discovered on a stoop smoking a cigarette. (Her discoverer, the label’s creative director, dubbed her “regal.”) After that, everyone wanted in: The Olsen twins, who became famous as infants and now run several fashion lines, chose to focus one of their 2014 look books on “something a bit different,” Elle coyly noted, meaning the style icon Linda Rodin, age 65. Marc Jacobs adopted Jessica Lange, then 64, and Nars scooped up the actress Charlotte Rampling, who was 68.

Perhaps the trend is a feminist rebellion against what happened last year to Renée Zellweger, the “It Girl” of 1997, who got skewered for assaulting us with a face that was “utterly unrecognisable” and “suspiciously puffy,” and for not understanding that in Hollywood, it’s been virtually impossible to age gracefully—so after 45 you should just disappear.

Or perhaps the young did themselves in, with their enduring obsession with kale shakes and BPA-free water bottles and salvaged-wood bar tables and fully strapped two-strap backpacks (recommended by the Pediatric Orthopaedic Society of North America), which suggests that the ineffable quality of youth we all lust for—a reckless hunger for life—now belongs to a generation still willing to sit on a stoop and smoke.

Photo credits: Rodin: Vivien Killilea/Getty; Didion: Walter McBride/Invision/AP; O'Shaughnessy: American Apparel; Rampling: Alessandra Tarantino/AP; Lange: Richard Shotwell/Invision/AP