It's well known fact that iTunes has changed the music industry. Some say for good, some say for bad, I say for...permanently. Other companies like Amazon and so on have followed suit, but iTunes remains the main reason that the industry's business model hurt.
To this day, it is amazing to me that places like Target and FYE can even attempt to still carry music at more than $10 an album. Very few people don't own an iPod or mp3 player, and NO ONE carries around a Walkman anymore.
Yoko Ono said in an interview with Reuters that it will be awhile until The Beatles catalog of songs will be found in the digital music scene. They(Ono, McCartney, Starr, Olivia Harrison) aren't "happy" with some of the thoughts and desires that Steve Jobs has for the catalog and it's distribution.
You cant buy Beatles music digitally.
Yet they still sell albums. Lots of them.
Perhaps The Beatles are one of the only groups that will be able to survive this digital transition.
I don't see Ke$ha sales performing the same way in the same situation.