How can you sit back and let people get on with things and yet have them deliver on time and in a coordinated fashion ?
I think a principal might be never to make guarantees on other peoples behalf. For example : you talk to someone and say yeah my guys can get that to you by next Thursday. This now means you have committed someone else to something they have not themselves agreed to. It might be more useful to have them talk to the party who wants something and then have them agree with that person to deliver said promise.
This relates to the idea of a team being responsible for deciding how much work they can do within an iteration. It is not one person but all involved who have committed to this amount of work. There is a group responsibility and this is much easier to run than the command and conquer approach.
Far from being unscalable to larger groups, you could argue that this level of decentralised drive is essential. However it is certainly possible for a single individual to provide the drive for many people , it tends to be quite autocratic though and can often make people feel threatened which is not an ideal environment for fostering creative work.