The problem isn't a lack of talented individuals with the right DNA... the problem is the system. In the US, kids that show any sort of fitness related talent are immediately funneled toward the US mainstream sports (Basketball, Football, Baseball). Sure there are a few (relatively) coaches with the eye, but that doesn't make it any easier to convince the kids to turn their backs on "the cool sports" and risk isolation from their peers while navigating the treacherous waters of middle school. Adding insult to injury, the majority of US schools are hiring grossly under qualified "coaches" (a.k.a. teachers looking to supplement their pay with a coaching stipend) that aren't in the least bit interested in developing younger athletes.
Another aspect (not necessarily limited to USA)... age grouping in USATF Youth (JO's) is heavily skewed in favor of the 1st quarter born, leading some born in the late fall (10+ months difference in development) to unjustifiably determine their potential as a runner before reaching full maturity, possibly leading to them leave the sport altogether. A well educated coach will help to mitigate this possibility by ensuring a proper perspective for a developing athlete, but again, the coaching talent in the USA is lacking (very few are educated professionals).
We (the USA) have the talent... have the numbers... but lack the proper system to identify, and cultivate the best of the best. If Bolt was born in the USA... very VERY unlikely he would have ended up in track and field instead of football, basketball, or baseball (three sports where he might have been just an average player - due to coaching, not lack of talent).