2. Because he has Yohan Blake and Asafa Powell as Training Partners
Usain's training partners are the sprinter who had the 100 meters world record before him, Asafa Powell, and the sprinter, Yohan Blake, who was second and third to him in the 2012 London olympics in the 100 and 200 meters respectively. When you add in the other members of his world record 4x100 meters Jamaican team, you can see that he will be pushed on a daily basis. These guys are hungry for the title of world fastest. Having natural ability is a very important ingredient to being a world class athlete, but it it the competition that makes you great, that makes you push yourself beyond what you thought you were originally capable of. Bolt has the requisite talented competition right at his doorstep, and he would not want it any other way.