I doubt we will ever see a significant market for music surround.
I would say 99.9% of the time 99.9% of people listen to music is in environments that are NOT conducive to surround sound. Think about when most people are listening to music:
Mobile playback devices (ipods, boombox etc...)
Car
Work
Stereo system in other room while doing some task around the house.
Music CD's/DVD's are already REALLY inflated in price, and trying to fit in surround sound mixes into the whole production equation would just hike up the prices even more. People just don't care enough about the alleged "benefits" of surround sound to pay anything more for it. Even if costs would stay the same, most people just would not appreciate it much, nor be in a situation listening to music to appreciate it.
So, Stereo mixes would STILL need to be done, now every song needs two mixes, stereo and surround? No way labels are going to pay for that!