I don't think these formats wars really have anything to do with sound. If you look at the general buying public, do they care about a hi-rez format? No, they care about convinence. When the 8-track came out, it was convinence. Then the cassette tape-convinence over reel to reel and records.
Now look at CD (the perfect sound forever) and it was the convinence of the format that drove it to what it is. (We could also say the same about VHS to DVD.)
How many people in this country participate in this little hobby of audio? How many people country wide have equipment that will let them know the difference?
When SCAD came out, it did not offer any convinence over what was already available. Look at this post at the number of people who say they can't hear a difference (which is mind boggling to me personally.)
This relegates SACD to a niche product for us anal rententive audiophiles. Will it continue to die, probably if manufacturers are basing its success on sales. Maybe it will go as the record, there will be limited production.
I don't think DVD-A will be any more successful for the same reasons. How much is this smallest segment of the population (audiophiles) worth to big business?
I think we should be worried if 2-ch will survive myself!