Anything you learn while young, you learn better and deeper than
something you learn as an adult.
Consider the way we learn languages.
As a child we listen and we learn. And later we just know what is the right way to say things. We cannot explain it, beyond "It just sounds right".
Compare that to learning a foreign language as an adult. You have to learn rules that doesn't make sense, and that you constantly forget. You learn vocabulary but will usually mess up the subtle distinctions. Trying to keep everything straight while talking is a constant battle.
Most human children have a part of the brain that is will eagerly grasp any language it comes across and learn it. Language learned this way become part of the permanent fundamental wiring of the brain.
Most human children, probably, do not have a part of the brain that is eager to learn chess.
However, some children get interested in chess at an early stage while the brain is still very flexible, and they repurpose other parts of the brain to process chess. Parts of their vision center is now a chess vision center. Parts of their memory is a dedicated chess position memory.
Some part of something becomes a dedicated chess move analyzer.
All this is part of the permanent fundamental wiring of their brains, below the level of reasoning.
As adults they will "just know" that some positions are strong and others are weak. They "just know" what will turn their weak position into a strong one.
They "just know" what will turn the opponents weak position into a lost one.
And they remember. Every position in every game they have played and very many games others have played and analyzed openings too.
This is not to say that these fundamental "hardwired" skills are everything. But they form the basis on which everything else is built.