When new component technologies (touchscreens, chips, LED displays) first come out, they are very expensive to produce, and building a factory that can produce them in mass quantities is even more expensive. Oftentimes, the upfront capital expenditure can be so huge and the margins are small enough (and shrink over time as the component is rapidly commoditized) that the companies who would build these factories cannot raise sufficient investment capital to cover the costs.
What Apple does is use its cash hoard to pay for the construction cost (or a significant fraction of it) of the factory in exchange for exclusive rights to the output production of the factory for a set period of time (maybe 6 – 36 months), and then for a discounted rate afterwards. This yields two advantages:
Interesting take – mostly about smartphones/tablests – Apple do not have the power and/or volume of orders to do this in personal computer space.