I think the sport is clearly on the decline in popularity. This includes a decline in 1. rec and league tennis 2. tv viewership has plummeted http://www.nielsen.com/us/en/insights/news/2008/us-open-historic-television-ratings.html 3. tennis equipment and apparel sales: I've noticed that tennis warehouse's selection of racquets, bags and shoes has diminished sharply over the years I've checked (2010 vs 2017). 4. impact on and visibility in popular culture. None of the top players is a mainstream celebrity. Serena Williams is widely reviled (even feared) and Sharapova is too ethnic as a Russian immigrant. Fed, Djoko, Murray are all Europeans and don't appeal to American fans. I do think the USTA is trying. However, the sport is just too fast and demanding for the demographic in which it used to have a stronghold: retired people. Played with wooden racquets, or even those crappy alu racquets, the game was played at a manageable speed. Now, with graphite racquets, even the weakest player can generate incredible pace on all shots, meaning that trying to play points means generating a huge amount of torque on your joints. I think tennis still has a future, but it's gotten very physically demanding at the same time that Americans have gotten fatter, lazier and far more technologically dependent.