Other super talented people want to work with a Jim Keller. So a company hires a Jim Keller not just because you want his brain, but because you can then go to the next 20 amazing people in the industry and say "come work on Jim Keller's team" – now you have 20 min Jim Kellers on your team and that is enough to move mountains in an extremely specialized field such as chip design.
That being said, even a strong team is still usually only as good as its leadership. You can have all the great ideas in the world, but if the organisation does not allow you to pursue them (or on the other extreme, allows everyone to work on what they think is best) you will still fail to execute.
At the end of the day you need someone to make the correct decisions every step of the way.
Having a good grasp of everything in the whole stack is obviously helpful for setting priorities and goals, and there's a lot of leadership skills involved in getting people to work together and follow the organizational goals. Having a track record of success is obviously helpful, too.