can't you hear samples before you buy? isn't that the same as saying "I don't know if I'll like this film, therefore I'll only pay 10p to go to the cinema and watch it". If only life were like that.
We could have a massive debate about the price of music versus the value but music costs money to make and it would cost a lot of money to make Radiohead what they are today. They can afford to pull a stunt like this now but bands starting out can't. You just have to give your music away for free in the beginning because no one knows what you're like, whereas Radiohead fans know what Radiohead are like, so you buy an album on reputation. That's why huge artists can release the occasional turkey album and people will still buy it anyway because it's them.
I'll stop there, sorry.