BTW, the "older" players are not sliding down a slippery slope either. The last time Mary Pierce was healthy was about 3 months after she won her 2nd Slam. Lindsay won her first Slam just 3 and hlaf years ago, at 22. Jen was almost 25 on her first, and a year later she is up to 3. Monica has been more competitive with the law firm of Williams, Williams, and Hingis in the past year than ever before. The firm of Clijsters, Dokic, Dementieva, and Henin hasn't even been able to take a match off her yet, despite all but the strongest of those 4 having victories over Venus.
Of course, the 30ish players aren't doing so well. Amanda is being outgunned, Arantxa is ordinary, and Conchita is dropping like a rock. But is that age or is it size (Amanda), motivation (Arantxa), and health (Conchita)?