There are examples of late bloomers.

Certainly. For expert performance early specialization isn't crucial, but I'd say it's quite important. I don't think there will ever be another Gennady Korotkevich (unless someone with a similar childhood comes around).

in adults the prefrontal cortex of the brain, where working memory is stored, is more developed than in children. A developed prefrontal cortex means that adults are hampered by a functional fixedness, causing adults to see a spade as a spade i.e a tool for digging. Or let me put that another way for you an adult sees a tennis racket or a shuttlecock as exactly that. However the under-developed prefrontal cortex in a child allows children to be far more inventive than that, as their prefrontal cortex is not limiting their ability to be creative and flexible. You’ll probably know this as “thinking outside of the box”.

So this is why a child can see a broomstick as javelin or the mattress as a trampoline. As a result, children are often better than adults at solving tasks that require a creative solution, such as being set a challenge with limited equipment.

The under-developed prefrontal cortex allows children to learn social conventions at a fast rate. This is because at this stage of brain development a child sees the most prevalent behaviour as the appropriate way to behave, hence the reason why appropriate adult role models are so crucial to a child’s social development. Interestingly, this ability to quickly learn conventions also explains a child’s ability to learn languages faster than adults.

tldr:

Put another way an adult’s brain is designed to perform, but a child’s brain is designed to learn.