This is the best comment on this subject. Good job, srjab!I think whether a 5.1 "fold down" from an Atmos mix sounds as good as a dedicated 5.1 mix is still very much an open question. From everything I've read, the fold down process can be controlled/affected by many mixing decisions and settings that can be largely automated or manually tweaked by the mixing engineer. Obviously, the responsible approach would be to audition the fold down mix and make adjustments if the result is substandard or audibly worse than the Atmos mix. However, going through that process may involve nearly or as much work as just doing a dedicated 5.1 mix in the first place. Depending on what was contracted for, any given mixing engineer may not be inclined to be that meticulous. They most certainly wouldn't audition a 5.1 fold down if a dedicated 5.1 mix was actually done.
For me, I would rarely listen to a stereo, 5.1 or 7.1 mix if an Atmos mix was available - unless there was something significantly wrong with the Atmos mix. However, I think it's far from proven that any 5.1 fold down is fully equivalent to a dedicated 5.1 mix, and probably shouldn't be presented that way. While this error is unlikely to be a problem for me, I can certainly understand why buyers that are 5.1 capable only would be concerned and would like some sort of correction to be offered. Any workaround that involves changing system settings to manipulate the Atmos mix for a single track will negatively impact playback convenience, if nothing else.
Personally, I purchase today’s surround discs for the Dolby Atmos track but I can see why there are many that are disappointed with the way the 5.1 mix turned out with the missing vocals on the one track. That is considered an authoring error and the label should step up by sending out corrected discs. Bottom line, people should get what they assumed they paid for and was advertised as what they were getting.