[deshpand]

Not sure why you were downvoted. Fitness, equipment (racket and strings) are the reason if not the height. For height, above a certain level, say 6 ft 2 inch, it starts becoming a liability in movement. Tennis used to have a lot of variety in the past. Big serve and volleyers on grass, long baseline rallies on clay, slice backhands, flat strokes. Now it's monotonous.. the surface doesn't matter. The game with the most payoff is to stand back at the baseline and hammer the ball.

On a somewhat related topic, fitness has taken over many sports. In field hockey, dribbling used to be a skill. India was unbeaten for decades in Olympics, winning 8-9 gold medals. The introduction of artificial turf ushered in the era of strength and fitness, and the Western nations mostly took over.