National heroes like Bjorn Borg in Sweden and Boris Becker in Germany have traditionally motivated a wave of youngsters from their countries, but next-generation Federer and Nadals have seemingly not emerged in Switzerland and Spain, respectively.
Between Federer, 33, and Stan Wawrinka, 30, Switzerland has two players in the top 10, but no one else in the top 200. But Federer has been at the top for almost 12 years -- long enough for emulators like Bulgaria's Grigor Dimitrov and Belgium's David Goffin to start winning titles of their own. But so far, those new stars have not been from Switzerland; its youngest players in the Top 300 are 23-year-old Henri Laaksonen (289th) and 27-year-old Yann Marti (295th).
Federer isn't sure why his achievements and popularity haven't led to more juniors coming through, but he points to the country having other, more established sports and a general culture of restraint. Though tennis has become popular in Switzerland, it has not created the sensation that Becker and Steffi Graf did in Germany.
"We have Stan. I mean, he's younger than me," the 17-time Grand Slam champion half-jokingly told reporters at Wimbledon. "You know, we have the Alps, which [means] clearly people lean maybe toward skiing, ice hockey, so forth. Soccer clearly is also very big.
"So maybe for tennis to roll in, like the way it did during the times when Boris and Steffi made their move in Germany, is never going to happen to that extent."
It took a while for Federer to make a huge impact at home. He did not become a big national figure until he fully established his dominance by the end of 2005, when he already had six Slam titles in hand, including his third straight at Wimbledon.
"It's harder to catch everybody's attention to Switzerland, to be quite honest. It took me a couple of Slams and a few years as world No. 1 for people to actually to realize I was doing quite unbelievable," he said.
The extent of the gap was vividly illustrated during the first round of Davis Cup this year, when Federer and Wawrinka decided not to play following their victorious campaign the previous season. With longtime No. 3 Marco Chiudinelli injured and Marti walking off the team when he was not picked for singles, it was left to Laaksonen and the retiring Michael Lammer to carry the flag in a tie that not surprisingly culminated in a defeat against Belgium.
The lack of upcoming players in Switzerland has not escaped the attention of its big-name players. "Yeah, for sure, we notice. We look at who is going to come [up the ranks], who is coming," Wawrinka said. "But so far it's not easy to find."
Rene Stammbach, the chief of Switzerland's national tennis federation, suggests the Federer effect could be delayed.
"Yeah, we have a big hole between [ages] 18 and 24, that's true," he told ESPN.com. "We have some very good juniors, 12 and 14. We have two good ones 16 and 17 years old."
Though Federer himself came through the federation's development program and his family has praised it, its facilities have been expanded with the extra funds generated largely through the impact of Federer's success. It has also hired four new coaches with professional experience, including Graf's former coach, Heinz Gunthardt, and Lammer.
"We'd, of course, like to have a broader base of players coming through," Federer said at Wimbledon. "I believe the federation is doing a good job. It's expanding the tennis center. They have more kids coming through there now again. I believe it's a good tennis school to go through. It's where I came through. I hope it inspires 'til some players to come through maybe in the next 10 years."
The atmosphere is more restless in Spain, which has become accustomed to having swathes of players on the circuit ever since the 1990s. The country also has two players in the top 10, and 12 in the top 100 -- more than any other nation. But more than half of those players are in their 30s. Nadal, at 29, is the second-youngest Spanish player in the top 50 at the moment. The only Spanish player under 27 in the top 100 is 23-year-old Pablo Carreno Busta.
"In 20 years, there was a lot of Spanish players," Carreno Busta told ESPN.com. "Now I'm the young one. I don't know why."
He widens his eyes when asked if he is ready to be the flag-bearer for Spain when the current leaders call it a career. "Of course it is difficult to be the same like Nadal or [David] Ferrer because [they] are really good players, the best in the world, so it's really difficult," said Carreno Busta. "I will try to do my best, and if I do my best, I will be very happy."
It might not be long before the No. 67-ranked player finds himself in the big leagues. Led by Nadal, Ferrer, Feliciano Lopez and Fernando Verdasco have helped turned Spain into tennis' biggest and five-time Davis Cup champions, but all are now closer to retirement age.
"This is something that is going to happen, and it is true that there are not so many players coming up," Lopez told ESPN.com. "I think [the] federation ... they have to notice and they have to work a lot in order to be successful in the future."
Lopez sees the depth and stars Spain has produced until recently, from Sergi Bruguera to Juan Carlos Ferrero to Nadal, as exceptional. But he also believes a drought approaching in tennis, saying, "We will have players in the top 40, top 50, but we won't have a bunch of players in the top 100, and I don't think we will have players in the top 10 either."
Spain's numerous tennis academies and the Royal Spanish Tennis Federation (RFET) usually join efforts to produce its assembly line of players, but it is the federation that is now under pressure to reverse the decline.
Nadal, one of the few who stayed at home in Mallorca rather than going to a center or academy to further his career, recently criticized the federation's development process.
"The Royal Spanish Tennis Federation didn't help a lot young players," he told reporters at the French Open. "And not only young players -- we, the experienced players. So we have covered a lot of ground ourselves without the full support of the Spanish Federation. We are not going to talk about the reasons.
"People will say that the Federation was short of money, but when I was 13 or 14 years of age, they offered me to go to El Car, but I thought the place I practiced was OK. I needed my parents at the time. ... That's why I stayed in Mallorca with [my sparring partner] Tomas ... and [he later] decided to go with the Federation. So they paid everything when he left and they didn't give me anything.
"I was given a poor deal. Then I took part in the Wimbledon juniors tournament and I had to pay for the hotel, for the trip, for almost everything. I decided to stay with my coach. I had to incur these traveling expenses, and all the players who were coddled by the Federation had their expenses paid. So this process, I mean, didn't work well."
For Carreno Busta, however, the federation had a positive influence, and could do the same for other players.
"In my experience, I have a lot of support from the Spanish federation. I stayed five, six years in the Spanish federation practicing. For me, I play tennis because the Spanish federation [paid for] me these years," he said, adding that some other juniors he played with are competing on tour, but generally below the top 200.
"We have some problems, but in five, 10 years, I think it's possible that young Spanish players will be good again."