I think Daniel and a lot of other poeple that listen to Cage's music aren't exactly listening to it the right way. I know Daniel and others (including myself) focus on the emotions music causes and value music based on that. If I go to a party I expect the music to pump me up. If you try to listen to Cage's music the same way you listen to music on the radio you will always be dissapionted. When you listen one of Cage's works you should mentally prepare your self for what you are about to hear. You cant expect the same qualities as "normal" music. You won't find emotion or even order in most of Cage's pieces. You can only expect to hear sounds with no real order.
As far as Cage's music not causing people to think I believe its almost the complete opposite. Cage's music requires thought in order to be appreciated. You have to understand the ideas behind his music. The average person couldn't hear "4 33" or "Variations" the first time and really appreciate it unless they learned about it first. With each peace you have to ask yourself, what is Cage's goal? In some cases he has no goal at all. This is something we are not use to. Almost all media now is passive, it tells us exactly what to think, feel, or pay attention to. John Cage takes an active approach, he invites us to think, feel, or pay attention to whatever we want and draw our own conclusion.
John Cage's music is not bad or pointless it just asks us to think and listen in a new way, but its up to us to make that call if we want to exprience sound in this new way.