In a way, that is all a bit beside the point, however.
"Her legacy is really wide, to the point where you can't even describe it in words. She changed the sport so much. She's introduced people that have never heard of tennis into the sport," said Naomi Osaka, a 25-year-old from Japan who has won four Grand Slam titles but hasn't played a full match since August and will sit out the Australian Open. "I honestly think that she's, like, the biggest force in the sport. That's not intentionally trying to make (Roger) Federer or (Rafael) Nadal smaller. I just think she's the biggest thing that will ever be in the sport."
In recent decades, folks might have worried about what would happen when Chris Evert and Martina Navratilova stopped playing. Or when Bjorn Borg, John McEnroe and Jimmy Connors moved on. Or Pete Sampras and Andre Agassi. Or Steffi Graf. And so on.
"It's always a loss when you have great players leave. But I've been through six or seven generations of this," said Billie Jean King, a two-time inductee into the International Tennis Hall of Fame who won 12 Grand Slam trophies in singles and another 27 in women's or mixed doubles.
"I mean, I remember when Sampras left and when Martina and Chris left. I was like, ‘Oh, no! What's going to happen?' Well, Sampras was there, and guess what? There's Roger Federer. There's Nadal. ... It's the same thing with the women. We've got Iga (Swiatek) now, who's taken over," King said. "Every generation gets better, and the depth of women's tennis is better than it's ever been, and Serena is somewhat responsible for that, because every generation builds on the last generation."
Shortly after Williams lost to Ajla Tomljanovic in the third round at Flushing Meadows, another titan of tennis,
20-time major champ Federer, announced his retirement. Federer hadn't played an official match in more than a full year because of a series of knee operations.
For Williams, there were moments when she stepped away from competing for stretches, either because of health issues or simply because she wanted to spend time on other interests, which she thought contributed to her longevity.
WTA CEO and Chairman Steve Simon thinks those gaps left room for some new faces to emerge in women's tennis, such as current No. 1 Swiatek and American teenager Coco Gauff.
"Serena has played what I would call a limited schedule over the last several years, anyway. So clearly, we have a new set of stars that are coming in and certainly establishing themselves and doing well," Simon said. "But I see us continuing to celebrate Serena — and I hope she comes back and plays another five or 10 years."
Good luck with that.