red book format was found to be sufficient enough in resolution and anything introduced to market later didn't work.
the answer is in market statistics whether it has or hasn't differences or whether it's worth the format or not.
Oh Ye of Little Format
Tonight our group of 13 people held a blind A/B/C test comparing
Formats of CD, SACD and Apple Sound.
We listened to one minute three formats of five different cuts
ranging from Pink Floyd, Dire Straits, Santana
Celine Dion, & one other.
The cuts were removed from the same CD using different layers.
Bottom line- Nobody zeroed in on anything! The Apple Sound actually
was slightly the favorite. Try it yourself.
Sound leveling software was employed and were the services
of sound engineer.
I always thought SACDs were nothing special.
Now if an XRCD had been included I think it would have been preferred
but you can perform the same test using XRCD due to the way
it is recorded.
The fun never stops here...