Strictly ratings. Every slam final involving the Williams sisters, Capriati, or Agassi has doubled or tripled any involving Federer. This is what the people want, this is what they get.
I remember back in the 80s (& 90s as well actually) when Espn would always show whoever was playing live(not just Agassi, Sampras, Connors, McEnroe on tape) & would actually switch to matches on outer courts if they were better than the Center Court blowout.
Americans cared more about Becker, Edberg, even Lendl than they do about Federer, Safin, Hewitt. Of course people actually still played tennis back then as well.
Should espn be thinking long term Camilio? I don't really blame them for their decisions, it's not their job to grow the sport. Even if they did concentrate on showing the best matches/players available, it wouldn't grow the sport. That needs to happen at a grassroots level to make people want to play again.
I really think growing tennis in the US is a lost cause, nothing can hapen to make it more than a niche sport. Nobody has cared about it for so long, why would that change?
The only hope is a McEnroe/Connors type personality emerging & dominating(& preferably be African-American, so the mainstream sports media will give tennis more respect)