In my view Apple has the what almost every other organisation lacks: strategic cohesion. They know what they're doing right now, they know where they want to go, and they know how to get there.
Put another way, they have a 'core competency' and they deliver against it.
Peter Day on BBC Radio 4 had a very interesting podcast about this very topic titled 'The Essential Advantage' which is well worth listening to I think.
This strategic cohesion is Steve's gift to Apple, and a lesson for every other organisation.