Here's a revolutionary take on the matter. What if Bolt's superior physical attributes combined with superior coaching has lead to his success? Superior coaching clearly has to be looked at when you consider the large number of Jamaican trained athletes who have had success at the highest level in the last few years. I know it's a tough pill for many on these boards to swallow - the idea that coaches from a small island could outperform coaches from wealthier nations, but it's more plausible than the idea that the small island's scientists are outperforming those of other countries.
Anytime a distance runner has any kind of success we see lots of threads on here asking about their training. What does Bekele do? How do the Kenyan marathoners train? Few here seem interested in what Bolt's training is like or in knowing more about Jamaican coaches. Much easier to assume the worst I guess. Or maybe it lessons the psychological trauma of dealing with the idea of being outperformed by others in areas you assume you should dominate.
One more theory and this is drug-related. There is quite plausibly a connection between drug use and Jamaican success. Here it is - the Balco crackdown caused the US and other drug cheats to start going clean, and this has allowed athletes from countries like Trinidad, Barbados, Bahamas, Puerto Rico, Panama, Virgin Island, Grenada, and of course, Jamaica, to even further demonstrate their worth on the world stage.