IMO Sony ONLY introduced SACD to stall DVD-A because they had Bluray in the works, and did not want the HD-DVD camp to have the DVD-A support..
Once Sony totally killed any hope for DVD-A, Sony basically abandoned SACD. This is my impression. Sony made players for awhile, but the Sony music never did really get behind SACD. IF Sony had really wanted to make SACD important, they would have made ALL releases on the Sony label in the dual format.
Now, the main supporters of SACD are small independent labels of classical and Jazz, which do not get carried in major mass market stores like Best Buy.
My personal assumption, is Sony may possibly go for Blu Ray music, If they thought it would be a winner. I think they will NOT do it because of hi rez downloads being more likely to take off. And becase Blu Ray has not dominated the market as DVD did when it came out. Plenty of folks (including myself) are just not impressed enough to go Blu Ray over DVD.