Kids don't like to experiment with their game, and usually stay in their comfort zone, which is to stay with the baseline game and not come to the net. Nobody likes to get passed or lobbed, and when the match is on the line they will hesitate to go in and take a risk.

It is true that there have been players who rely strictly on a baseline game who have done well on the pro tour, but if we look at the top men and women in the world we will find that in the high levels they all have a variety of shots with which they hurt their oponents.

Roger Federer is the perfect example of a player that has every shot in the book, which allows him to change his game according to the surface and the oponent and to dominate the world ramking. In the women  Justin Henin is an example of a player that comes in a lot, about 15-20 times per
match (on hard court).