Tennis is a victim of technology.
Americans play what they like to watch on TV. That's why we play baseball and football and basketball while we don't take to hockey and soccer. In the 80's tennis was great on TV, the matches were exciting, the players highly skilled, the coverage made for excellent viewing and the tennis courts around the country were PACKED!
When wide-body rackets hit the pro tours the game changed. Power replaced skill, serve and volley replaced rallies, matches got boring as every point was boom-boom, over instantly. The game started to suck, it wasn't worth watching anymore. If it's not fun to watch on TV nobody plays and if nobody plays there's no fan base to watch on TV. It's a downward spiral.