With Venus, the former world No. 1 is now out of the top 100 and her climb back into contention for a major title looks to be near impossible as her health problems mount.
Additionally, she is in the above 30 crowd on tour, not a great spot to be. Being on the wrong side of 30 and ranked out of the top 100 doesn't exactly imply future Grand Slam titles.
Serena, a little younger than Venus, is currently ranked 12th on the women's tour. The 13-time Grand Slam singles champion can certainly tally a few more majors before she too just gets too old to compete.
However, she could fall flat on her face as well and perhaps the next major will provide a lot of insight.
The 2012 Australian Open is a couple months away and the event is her best Grand Slam in terms of singles titles. Her success at Melbourne Park, or lack thereof, should show what she's made of at this late point in her career.
Looking ahead a few years, American women's tennis appears as though it will be in pretty capable hands.
Sloane Stephens of Florida is the youngest player inside the top 100, certainly implying future success. At 18, and there is no one near her in the rankings as young. Laura Robson, ranked 131st, is a full 10 months younger than Stephens.
Christina McHale is another American player that appears to have a bright future. McHale was born in May of 1992 and she is currently the third youngest player in the top 100.
The teenager enjoyed a fine season in 2011 that saw her defeat players such as Svetlana Kuznetsova (twice), Caroline Wozniacki and Marion Bartoli.
Serena Williams will keep American tennis fans interested in Grand Slams for the next couple seasons. After that, Stephens and McHale should have developed enough to start making the second week of majors.
McHale is the one to watch as she already has victories over very accomplished players. Perhaps in a year she might crack the top 25.