You already have ala carte. Ala carte music. And while indies make inroads, its a shrinking market dominated by the majors. Which in turn makes it harder and harder to find music. There are so many locations to look for music, you have to know the web to know which bands put their music on which sites.
Sure you can go to Itunes, but thats 99c a song and possibly going up in price. Thats for a song. A song that costs relatively little to record.
You already have ala carte with movies. You can go to the theater. You can buy or rent a DVD, or sign up for a subscription service and pay 10 bucks and up a month. Pricing starts at 29.95 for the dvd and goes down the longer you are willing to wait to see it.
Ala carte doesnt make it cheaper, it makes it more expensive.
Ala carte means complete uncertainty for the content producer