Ars Technica has a great article about how the consumer has shifted from album purchases to singles. Many artists including Kid Rock, AC/DC, and Jay-Z have boycotted iTunes' approach to only allowing tracks to be sold individually, versus forcing a consumer to buy the whole album. What Apple has done is change the whole landscape of how consumers approach music. No longer are we bound by the chains purchasing a $10-$20 album, if all we really want is a 99 cent track.
The economics for the artist are quite simple. They make a much greater amount of money on the sale of a full fledged album than a drip of a single. But when you bring in the consumer, the matter seems very clear: they want choice. From my view, it seems that a lot of time is spent producing a good, decent (ok, sometimes bad too) single, while the rest of the album is filled with throw away songs. To be made to purchase a full album just for a song seems too steep a price to pay.
One point that the article brings out is that some albums really should be consumed as a whole, but it seems that it has been a long time since I have listened to an entire album and thought that there was something worth more than the sum of its parts. When artists get all persnickety about people only wanting a song or two, maybe they ought to look at the overall package.
We're voting with our dollars and in the end this consumption model doesn't seem to be disappearing anytime soon. Which brings us to the real crux of the argument: business models have to adapt to changes in the consumer landscape. If not, you can keep your 'albums only' mantra and find a new way of making your living.