The titles listed in this thread are existing quad and 5.1 mixes created years ago, that are probably fairly trivial to package as "Dolby Audio" titles in Apple Music. As for all the new releases and newly-mixed classics that are actually Atmos and listed as such, I share your amazement that Apple has put their considerable weight behind a push for this content. They apparently have a lot of leverage with the record labels to get them to fund creation of new Atmos mixes, but as we've all observed, the quality of the mixes can vary greatly, which may be due to a lack of qualified / experienced engineers to suddenly do all this work. Maybe that's better discussed on one of the Atmos threads though.As we've discussed a lot, he amount of Atmos stuff flowing to Apple TV is quite something. But I really don't get it, frankly. Although many titles have surround masters already available, I can't imagine "Atmos-ing" being a trivial task...or are there just a plethora of mixing engineers that have kept all this quiet for some time?? I'm not complaining, I'm just trying to understand.
In any case, we can only hope it continues, both the old stuff as Dolby Audio and the new Atmos mixes, and that Apple doesn't eventually give up on Spatial Audio, if it doesn't prove to be popular enough.