curtis, your question has one fatal flaw. Motion is not the only factor that contributes to the breakdown of a material. Sunlight and even plain old oxygen will eventually break plenty of things down. Imagine a pair of speakers fresh out of the box and played for about 50 hours and then not again for another 50 years. More than likely, the 50 years of exposure to the in-home environment would affect the sound more than the initial 50 hours of play.