It's a variation of Microsoft's EEE. Easier one because most of the loudness was already there. They did not have to create a problem now, it was already on the table (done by the same music industry which is suposedly fixing it now).I don’t have any idea why the Atmos mixes are so much better (just look at those Audacity wave forms!), I kind of doubt that it happens on the Mac during stereo down-mixing. It would be magical if it did. I’m assuming that whoever produces the Atmos mixes for Apple Music just take great care or has access to better masters. Or perhaps that Atmos necessitates a better dynamic range, crest factor, etc. No idea. In the end, it’s the result that counts. I’m not here to wave the Dolby flag, just wanted to point the stereo folk at something worthwhile giving a try, that happens to be Atmos related.
I think you’re conflating a few things here. It wasn’t Meridian who created the loudness wars. I also don’t remember MQA tracks to sound better (or even significantly different) than their regular versions.
Those better sounding tracks were simply remixed/remastered. Take a crappy old release, remix without the loudness and then sell it as "better sound because MQA/Atmos". The better sound has nothing to do with MQA/Atmos, that's just 'packaging'.
A better remix will sound same as better without any single trace of MQA/Atmos involved.