All the above listed are the biggest names in tech today. There are others, Gates, Ellison, Zuckerburg, but I don't consider them as talented as the ones I listed.
Managing large, sprawling corporations is nothing like starting a company with a few products. I'm not saying it's harder, but it requires a different skill set. Neither Musk nor Graham have a proven history managing large and diversified companies. MS doesn't want them, and I seriously doubt they'd even be interested in the job. It'd be like recruiting Lebron James to play baseball.
A large company is just a large number of small groups.
A startup is a small group.
PG is someone who has proven effective at managing to give a big ROI from managing quite a few small groups. Hence he is eminently suited to running a large corporation.
Buzz, created by Steve Jobs, much of it from his pioneer status from the 80s. They had a built-in market to whom they can sell high-priced items (Apple fanboys) where they recoup costs. Then, after that, they make profits from non-fanboys. (They don't like to talk about this, but that's how they internally plan it).