"I don't know if someone in the next 10 years will be able to win five or six Wimbledons," Sampras said on a conference call Monday ahead of next month's visit to Toronto for his induction into the Rogers Cup Hall of Fame.
Sampras, who will also play in the Rogers Legends Cup, and Federer each have seven singles wins at the All England Club.
Scotland's Andy Murray won his first Wimbledon title earlier this month.
"This was Andy's time, it was Andy's event to go and get and he did it," said Sampras. "He's definitely the man to beat at the U.S. Open."
Murray is currently ranked No. 2 in the world behind Novak Djokovic, with David Ferrer at No. 3, Rafael Nadal at No. 4 and Federer at No. 5.
"I think the biggest thing for me is Murray in the past 12 months has just stepped up," Sampras said.
But he doesn't see anyone being able to conquer Wimbledon's grass courts the way he and Federer did.
"Roger and myself, our game on grass was so ... dominant," Sampras said. "I think Murray can win some more and Djokovic, but I don't think that dominant game is out there that's going to win it seven times.
"But I could be wrong."
Of course, there is always the possibility Federer could add another. After his second-round loss at Wimbledon this year, he switched to a larger-faced racket to try and improve his game.
"I don't know where his head's at, whether he's going to stick with it," said Sampras, who switched to a similar racket after he retired.
Sampras says it helped his backhand and provided more power on the serve.
"I wish I would have tried it, at least a little bit on the clay, when I was playing," he said. "It would have helped me a little bit."
As for Canada's top-ranked men's singles player right now, Milos Raonic, Sampras says he has what it takes to win a major but it takes time to get there.
"He's got a huge game and a monster serve and he competes well, he does everything really, really well. It's just a matter of getting experience, putting yourself out there against the best players in the world," said Sampras. "It's just a matter of getting over that next hurdle.
"Maybe he's got to work a little harder, maybe he's got to push a little more, it's such a physical game today."