Earlier quoted context omitted.
You probably can't go wrong with giving your child resources that's too expensive for other children to be exposed to for some free future competitive advantage (which translates to adult success), as a general first heuristic.
AKA how Bill Gates because Bill Gates. One of the very few kids to have access to a computer at the time.
He also chased programming like a starved Tiger, doing things like looking through corporate trash bins for source listings and that sort of stuff. Not to mention that Allen was also a person of extreme intellect and Ballmer is actually a mathematician combined with a charismatic business brain and a small nuclear reactor in one.