It's just not possible, there are thousands of people who contribute to the Linux kernel. I believe I saw a chart a while back that showed two or three levels of hierarchy between Linus and contributors. Realistically, you run a small team of people who run other small teams of people who....
And because of that, it's entirely possible to be at the head of an organisation made up, primarily, of far better people than yourself.
Heck, it's highly probable that's going to happen if you fall far beneath the average in social skills and have significant leverage along some other axis. Nice people will generally refuse to work with an arsehole - but every now and then someone will, (maybe because they have thicker skin than the average, or value your leverage more, or come in for less of your flak.) So, the people who are nice and will, for whatever reason, put up with you tend to end up filling those positions because no-one else can do so effectively. If they're nasty, then no-one will be more likely to work with them than they are to work with you and the problem recurs one level down - except this time you need to find people'll who'll work with five (or whatever the size of your immediate project team is) arseholes rather than one to make the project work.
This all, of course, depends on the alternatives that the people at the base of the hierarchy have. In situations where the people can't go elsewhere it often seems to be very much a case of, 'You'll take it and like it, if you know what's good for you.'
Does any of this mean Linus is bad at running teams? No. But it does mean that he's not necessarily any good at it just because the system's giving reasonable output. The naive model of a hierarchy as something in which all the influence flows from the top down is nonsense.