Charlie Kindel, with some additional thoughts to Horace Dediu’s aforelinked article:
[Apple] only focuses on one customer: The Consumer.
In my experience, the behaviors and culture of an organization (large or small) that focuses on the Consumer as a customer is diametrically incompatible with the behaviors and culture of an organization that focuses on Business as a customer.
And, by extension, Mac and iOS 3rd-party developers have the same mindset. Thus the whole ecosystem is one which focuses on the consumer.