That same type of unprecedented parity is happening in the WTA, too, with 13 different champions from 13 tournaments.
No tennis season in the Open era's 50 years ever started this way for the men or women, let alone both. As the tours shift to the Miami Open this week and next, there is a level of depth and a lack of supremacy that Federer, for one, finds intriguing.
"Definitely says something about (how) there is shifting going on, on both tours. That it's maybe harder to dominate. Or it's harder to keep on, sort of, having the same winners," Federer said Wednesday. "And the young guys are really pushing through, which is a thing we've been looking at for some time now. It's just not easy winning tournaments, and it seems easier for them now, which is good. And it doesn't mean the other people are not as good. It's just that there is a shifting going on."
Never was that more apparent than last weekend at Indian Wells.
Dominic Thiem, a 25-year-old Austrian without a Grand Slam title, won the men's final against Federer, a former No. 1 with 20 majors who is 37; even more strikingly, Bianca Andreescu, an 18-year-old wild-card entry from Canada who'd never been ranked in the top 100 until January, triumphed in the women's final against Angelique Kerber, a former No. 1 with three majors who is 31.
"We kind of can see that everyone's sort of at the same level," said current No. 1 Naomi Osaka, "and it's basically whoever wants it the most and is willing to put in all the work."
She won the past two Grand Slam tournaments; the Australian Open was her lone championship of this wide-open season. Novak Djokovic won the last three majors, but he, too, managed to hold a trophy only once this year, in Melbourne.
Who hasn't given a champion's speech in 2019? Serena Williams, whose last title came while she was pregnant at the 2017 Australian Open.
The superiority that Williams, Federer, Djokovic or Rafael Nadal sustained for stretches in the past has not been on display by anyone.
"Everyone can believe more that there is a chance for everybody," said Simona Halep, the reigning French Open champion. "And the fact that the tournaments are open makes it more interesting, also, for the fans."
Then she joked: "And also for us. It's not like before, (with) Serena winning everything."
As with any sport, of course, there are new names that pop up here and there in tennis every year.
It's just that there are more of them arising currently.
"A lot of people who don't watch tennis regularly are only familiar with one or two faces on each side, and that's kind of it. By having so many champions and so much depth, it forces players to keep trying to improve week to week because they know whoever they're going to play is going to give them a run for their money," said Danielle Collins, a 25-year-old American who was 0-5 in Grand Slam action before a run to the Australian Open semifinals. "For the spectator side, it's going to educate people more about more of us and how good of us some of us are. That helps promote tennis."
Federer pointed out that there are those who will find a reason to gripe, no matter what.
As in: One player wins everywhere? That's boring.
Or: A bunch of players divvy up everything? Ugh, no one knows who they are.
His take?
"I actually think it's always good, whatever happens, to be honest. I see positives all around. I came through a time where guys were dominating, and (then) they were not, and then there were multiple winners — and people always thought about it quite negatively," Federer said. "It was never, ever right. I always see it as it's always, always good. Because there's always fascinating stories."
He is not so sure the ATP's 19-champions-at-19-tournaments trend will continue.
"Clay is coming up; that's Rafa's territory. I'm sure that Novak is going to be really, really tough to beat here," Federer said. "Maybe we'll speak again in a few months and everything's back to 'normal.' I don't know. But it's definitely good what's happening right now."