Their assumption is that Apple are a software company, whereas most pundits assume the opposite: they are a hardware company, with the OS being a loss-leading differentiator. I prefer to think of them as more of a Nike: a brand representing a philosophy. The key for such a company is to set the tone of your market, whatever that may be, to maximise customer loyalty. Loyalists buy you because you're the best, and the 'cool factor' wows the initiates. Who assembles Apple computers? Who cares? Only Apple need to care because their brand assures the customer that they will receive a high quality purchasing experience. If Apple felt they could get a better production deal from Dell, I'm sure they'd happily bring them on board as long as it didn't diminish their brand.
To use a car analogy: Ford owns Jaguar, but Jaguars are not Fords, and never should be. [Ford tried that with the early X-type and it flopped].