Jon,
I remember discussing with students when CDs first appeared the possibility of recorded music eventually being available in a ROM-like format. (One of the things I teach is digital modulation/encoding). I still think it will happen for the same reasons you do but it has a while to go. Even using compression, e.g. mp3, memory capacity & cost make the idea impractical at the moment. The Diamond Rio mp3 player is a start, but it just doesn't have the capacity or cost effectiveness it needs at present. I'm sure there's a place for it, but the idea is not ready for the masses yet.Cheers,
Alan