In digital radio systems, several variable bit-rate data streams are multiplexed together to a fixed bitrate transport stream by means of statistical multiplexing.
The frame-level quantizer is either dynamically selected by the encoder to maintain a certain user-specified bitrate, or (much less commonly) directly specified by the user.
Furthermore, satellite providers have access to very expensive state-of-the-art MPEG encoders that can provide unsurpassed quality at very low bitrate.
But if you're an audiophile or at the very least someone who appreciates well-rounded, natural-sounding high-bitrate music, these earphones are brilliant.
