It may be king but it's not perfect, since it uses lossy compression to store the data, which generates artifacts that are noticeable when listening to MP3 music on a quality sound system. As memory becomes cheaper I would think there would be more use of one of the lossless compression schemes, such as FLAC. That gives you CD quality at about half the storage requirement of a CD (wav file).
Yes, I forgot about FLAC.
I wonder if the same thing will eventually happen to digital cameras; will they start using PNG rather than JPEG when memory carts start to come in Terra byte sizes?
Maybe even the same thing will happen to video but that's a long way off from now.