Doesn't sound like you are.
A potentially clean world record holder- You mean someone that could run 9.58 clean? Then no, I don't think that person exists at all, or will exist for several decades.
The point I think you're trying to make is that the worlds fastest 15 year old should be expected to be the worlds fastest 15-20 years later, also.
I disagree.
The fastest 15 year old is likely the one who peaked earlier.
Here's where I made that point before
So lets look at the hypothetical peak/decline curve. The graphic is from baseball, but whatever.
http://www.baseballprospectus.com/news/images/4464_1.gifExample of athletes who perform well at a young age, J-Mee Samuels, Obea Moore, Alan Webb, show that it is not that their curve was higher, but that it was shifted to the left: they peaked earlier.
The person who is the age-group world record holder at 15 is rarely the person who goes on later to dominate the sport. Here are the U18 records:http://www.iaaf.org/records/by-category/u18-world-best-performance Only Bolt is a current senior WR holder in track events (that list is subject to debate, age-cheating and such, but off-topic). Change the display to U20 and you see the same thing: Bolt and Shaheen are the only current senior WR holders.
Because performing well at a young age is about being closer to your peak earlier, not about having an absolute higher peak overall.
I don't believe that any individual can be as much of an outlier (as is Bolt, for example). Someone has to be the best, but the differences between the first and second best shouldn't be large. The stars align to make one individual the best, but the likelihood that almost all the stars align for other individuals is much higher.
Imagine a standard distribution curve.
http://www.mathplanet.com/Oldsite/media/27934/normal_distribution_500x263.jpgThat means that the best individual isn't that much better than the next person, and there are increasingly more individuals performing at lesser performance levels.
The best individual certainly can't be that much better, so as to dominate at every age, even to dominate athletes who peaked at those earlier ages
That's the point is seems you misunderstand.
For everyone else reading, here's the rest of my thoughts on his progression