Novak Djokovic cites the depth of play, physicality of the game, and ranking points system as three reasons why there are so few teenagers in the Top 100.
"We didn't have so much young players so successful at the top of the men's game," he told reporters in London. "Maybe [Milos] Raonic and [Bernard] Tomic, they're one of the two guys that managed to get to Top 20, Top 30 of the world, but not more than that. Maybe it's the competitiveness nowadays. It became more physical. Not just that, but also points system. I think it has changed. It makes it much more difficult for the lower-ranked players to make a breakthrough. The distribution of the points is different comparing to what it was in the past system."