I quoted all of this so anyone reading this thread can go through it again.
The 'talent' mentioned, and I notice this because I'm also the father of a talented junior, is the common situation that the early achievers are 'beasts', or 'bosses' as Americans say. Either that, or they are 'whippets' who just zip along. For a variety of reasons, they stand out at a young age, and, as mentioned, are hammered with high-end aerobic, and then anaerobic workouts. Base is virtually ignored, even disdained. This is a fatal mistake.
These guys, eg Alex Rowe in Oz, can get really, really fast. But, ultimately, they fail because coaches have foolishly ignored the bedrock running that you put the fast stuff on top of. As my mate would say, you are sharpening a pencil with too little lead.