Is Tennis in the US on Life Support?

On the WTA, I don’t think this is the case even if Serena Williams is not considered due to being over 30.  A group of young and talented US citizens play on the WTA Tour.  Odds are that someone of this group will emerge as a top flight player.  On the ATP Tour, things are much more grim.  Consider that Tim Mayotte lost 7 times in Grand Slam quarterfinals. US #1 John Isner has reached 1 Grand Slam quarterfinal.  Tim Mayotte also reached the 1982 Wimbledon semifinal round, and in 1983 he reached the Australian Open semifinal round.   Tim Mayotte was 2-7 in Grand Slam quarterfinal matches.  The entire men’s roster excluding Robby Ginepri is 0-3 in Grand Slam quarterfinal matches (Isner 0-1, Fish 0-2).  Is Tim Mayotte considered to be an all-time US great?  Mayotte’s results in this era would…