“Apple makes more money from the sale of one Mac than HP does from selling seven PCs.”
That’s a direct result of Apple owning their own hardware and software stacks, and so are able to deliver seamless end-to-end services, integrate peripheral products such as iPods, iPhones etc, and then charge more. That’s why HP bought Palm.
In a related sector, did Nokia think this through before jumping into bed with Microsoft? They will have few of these options open to them, but could become just another handset hardware manufacturer.