I'm going to propose an alternative explanation. This distinction doesn't exist, or at least not the way it seems.

The "fast thinkers" aren't thinking. They're just doing. Everyone is not only capable of this, but probably behave this way several times a day on certain tasks without realizing it or how it seems to others.

This is beyond mere practice towards a narrow goal. Certain topics just click better due to seemingly unrelated, yet deeply integrated life experiences.

It's not something to worry about since, as the article states, it doesn't affect outcomes much. If anything, "fast thinking" creates blind spots.