Perhaps we sometimes expect too much. You don't listen to music to remember the lyrics, you just enjoy it. And you can enjoy and discard a piece of writing too.
You can easily idle away time. Right now I'm procrastinating.
We know that it costs Apple about $300 to make a $500 iPad 2 and the cost of making an iPhone is known, too, and that cost is a lower fraction of the price they get (from the carrier or retailer) than it is for Macs. Of course, Apple had to spend many billions to make the first iPad 2, and the $300 does not include support costs (which I think are fairly minimal).
Point is that it is known that most of Apple's current profits come from iOS device sales. Also it is a pretty safe bet that the profit on music and video entertainment sales is fairly low as the owners of the music and video entertainment are very good at negotiating. Finally, Apple has stated that profit from app sales is much less than profit from even the least profitable hardware lines (currently iPod and Mac).
It is interesting to note that even Apple and Microsoft do not know the net income of the various divisions: since the success of the iPod brought new interest and new credibility to the Mac line, thereby increasing Mac sales significantly, and since it is impossible to know exactly how much Mac sales were increased by this "halo effect', it is impossible to know how much of the cost of developing the iPod should be assigned to the calculation of the net income of the Mac division.
Similarly, Microsoft and everyone else knows that the immense market share of Windows in the 1990s among consumers helped Microsoft's products to compete against offerings by IBM, Lotus, Sun, etc, in the enterprise market where Microsoft currently makes most of its money, but it is impossible to calculate exactly how much of the cost of acquiring those consumers as customers should be allocated to the Business division and the Server and Tools division.
Finally, for part of its life, Visual Studio was given away to qualified developers because the availability of more apps for Windows was seen as protecting and assisting that business, so a calculating of the "true cost structure" of, e.g., the Windows and Windows Live division and the Server and Tools division would have to take that into account.