Serena Williams, likewise, talks endlessly of the joys of motherhood, but still cannot scratch the itch of trying to equal Margaret Court's mark of 24 grand slam singles titles. Before Williams, it was Martina Navratilova - who succeeded Court at the very top of the women's game - who squeezed every little success out of the sport before she departed. Not only did she claim 18 grand slams, but an additional 41 doubles titles culminated in a 59th and final championship at the 2006 US Open weeks before her 50th birthday.
For Barty, just three years old when Williams won her maiden US Open and 10 when Navratilova finally called time, the equation is framed very differently. She is perfectly at peace as a three-time major champion on three different surfaces, unperturbed by any reminders that she still has the "career slam" to complete in New York. She will doubtless be inducted into tennis's Hall of Fame in Rhode Island, but is unlikely to find - in common with every other athlete outside America - that it makes much difference to her life.
One explanation for Barty departing the stage so young is that she is, at heart, a homebody, the beer-and-Vegemite-loving girl next door. "I can't wait to get home to my family," she said, having fulfilled her lifetime's quest to win Wimbledon. At the height of the pandemic in 2020, she opted against defending her title at Roland-Garros, preferring to relax in Brisbane with a lager in hand while watching Australian rules football. Not for nothing has she been quasi-beatified in her homeland, heralded everywhere as "our Ash". But her retirement is also a telling signal of a shift in attitudes.
Barty's love of soothing, normal routines - she identifies her favourite mental escape as vacuuming - is hardly unique at the top of tennis. No sooner does Nadal lose at Wimbledon than he is spotted on the beach in Majorca. What is different is Barty's idea that eventually, one of these worlds needs to be traded in for the other. For Nadal, 35, domestic bliss can coexist with the pursuit of sporting immortality. For Barty, only a permanent break from a life on tour can enable the freedom she craves.
Have athletes forgotten what it means to be obsessive about records? Is endurance at the highest level a dwindling commodity? It is Barty's prerogative that she should leave on her own terms, but it is apt to ask how soon, as a woman of leisure in her mid-twenties, she will become restless. It is a moot point whether the adulation of Centre Court can easily be exchanged for the more humdrum charms of suburban Queensland.
Look how quickly Tom Brady tired of the transition from celebrity to obscurity. On the surface, he was adapting well, at 44, to shedding the cloak of seven-time Super Bowl winner, taking his sons to watch Cristiano Ronaldo score a hat-trick at Old Trafford. The very next day, he reversed his move to retire from the National Football League.
A widespread view persists that Barty's retreat is temporary. Kim Clijsters, Justine Henin and even, briefly, Bjorn Borg attempted comebacks. But it would be wise to temper any certainties. For Barty is the product of her generation and of its acute sensitivities, where, in the balancing act between sporting longevity and all-round peace of mind, there is increasingly only one winner.
The Daily Telegraph