I'd tend to lean this way. Keller is someone who could generally call any chip company in the world, and have a top job tomorrow. Not some scrappy dreamer who's just trying to steal customers from a big player.
The field itself is already pretty niche. The amount of people on his level probably fit on an index card. That helps probably the most.
He's obviously a smart guy, but to me his wisdom comes from being able to actually understand the system and explain it. Whether he actually codes it or is even that smart becomes irrelevant, he has the ability to big picture it and get aces in their places.
But mostly the first point. The niche is so small you'd probably be hard pressed to find someone in comments who actually has worked alongside him to even attest to any of this.
It's immensely clear that when he goes somewhere, some big advancement usually happens, and he can explain why. Even if that's -all- he knew, it'd be enough to make him super valuable. So if we have to keep going back and pinning traits, I'd say it's some amount of intelligence mixed with a whole lot of passion.
How does someone achieve this? Raw IQ? The right schools? Right place/right time? Luck + effort?
Is there something a moderately intelligent person can do that has a high likelihood of moving them in this direction (if not actually achieving it)?