This thread was started in 2008 when the topic was relevant. It is interesting to read the newer comments, all of with which I sadly agree. I personally own around 209 classical SACDs. Classical and jazz listeners kept the format limping along for a while.
IMO it failed because:
1) it was initially tied to multichannel. The failure of multichannel is a whole separate topic that deserves its own discussion, but said failure was an albatross for SACD, DVD-A, and BluRay Audio..
2) While sonically superior to CD, it wasn’t the night and day superiority that stereo offered vs. mono. Many people couldn’t perceive enough of an improvement to think it was worthwhile.
3) most importantly, shortly after its release, all physical media began to be supplanted by file sharing, downloading, and ultimately streaming services. Convenience initially supplanted sound quality, as it was easier to store music on an iPod or other portable device and headgear than a full scale system. Eventually streaming services upped the ante on sound quality so the small group of people who realized after years of mp3 listening that they were missing something were largely satisfied