How do you prove the game is slow then?
1. you can start with the existing data for example:
- evolution of service speed
- evolution of rally strokes (forehand / backhand) speed
- evolution of winners speed
2. add here the court dimension
3. add the time the ball spends in air before the bounce with time in air after the bounce
4. try to imagine how much the courts should have been slowed down, to make the game slower than it used to be some 10 / 20 / 30 years ago
I mean, if for example, 20 years ago the ball required precisely 1.00 second to travel from player 1 to player 2, and the speed of an average rally shot increased by 20-30 km/h, by how much the court shall be "slowed down" to compensate for the increased speed in the shot production, and actually to slow down the entire game, to let's say have 1.20 seconds currently as time required for the ball to travel from player 1 to player 2