I saw a similar thread to this a while back. Granddog was predicting that Serena would win 25 Slams. I wasn't then a member, so I couldn't get involved in the discussion, but it's worth raising again now. When Granddog broke down which Slams Serena would win, I think her/his prediction was that she'd get two Slams in 2014, two in 2015, and one in 2016. At any rate, it was certainly five in the next three years. That would leave her needing three in 2017 and beyond to get to 25. I know that her dominance at 31/32 is unprecedented, but I still think that it's way too early to be predicting that she'll win three Slams AFTER her 35th birthday. There's a good chance that, by 2017, someone we've never heard of will be ripping it up. A truly world-class player at the peak of her powers would have a huge advantage over a 35-year-old world class player.
Navratilova is the most recent woman to have been competitive deep into her 30s. At 32, Navratilova was way behind Graf, but she was still an almost equally long way in front of anyone else. (In fact, Navratilova's overall level of performance at 32, in 1989, was probably better than it had been at 31, in 1988, but that's another story. For whatever reason, Martina lost motivation in the first half of 1987, when she was 30, and it was a couple of years before she regained consistent focus, even though she got it together sufficiently to win Wimbledon and the US Open in 1987, when Graf was still too raw to challenge her on surfaces that favored Martina).
Had Graf not taken up tennis, there's a decent chance that the 32-year-old Navratilova would have been a dominant #1. But Martina's level in 1992, when she was 35, was quite a bit below her level in 1989. True, she was still a very good player, and true she made a Slam final as late as 1994, when she was 37. She should really have won that Slam final. But, by 35, her level was not high enough to have been a dominant #1 in any era. Not only were Seles and Graf way in front of her, but even lesser players such as Sabatini and Sanchez had caught her up and marginally surpassed her. Martina was still an excellent player, but she ended 1992 as #5.
Even if, in 2017, there is no world-class player on a par with Seles and Graf around, there will surely be near world-class players on a par with Sabatini and Sanchez around. Azarenka will be 27 for the first half of 2017, and will turn 28 at the end of July that year. She might even be slightly better than Sabatini or Sanchez, and so she should be at least roughly as good as Serena by then, if not a tad better.
And that's probably a best-case scenario as far as Serena is concerned, because, by 2017, there will probably be someone a little better than Azarenka around.
