I think you're missing one of the main points, which is someone using other headphones is still getting the atmos version, but in normal stereo - and when that happens, large parts of the balance of the mix are lost as he explains in the section on What's Going On. So it's not the original track as the artist, mix engineer and masterer intended you to hear.

I don't think that's true? There's nothing special about Apple's implementation of Dolby Atmos over headphones besides the head tracking bit (and that's not needed for music) that need their headphones. If you set Dolby Atmos to "Always On" in the settings it will give you the Atmos headphones mix regardless of what headphones being used. Airpods and Beats are still just stereo headphones.

Atmos works pretty well over normal stereo headphones and I've used it for years on PC while watching supported Blu-rays.

I'm kinda peeved at Apple's lazy implementation because it's only supported on Apple devices and not devices that support Atmos and work with Apple music like a PC or Samsung Android phone.

It’s supported in the beta version of Apple Music for Android.

I initially thought the same on another article, however it turns our spatial audio in the apple music sense, is not exclusive to the pros/max - despite sharing the same name as the head tracking-esque feature in those headphones.

Quite disappointed as it is quite obviously confusing

you're conflating unrelated things

6dof has nothing to do with SpaTial audio and no AirPods Pro/Max weren't designed 'in tandem with' it

you'll get Apple's positional audio (6dof) only with supported hardware - which includes AirPods Pro/Max, iPads and AppleTV - and is designed for positional listening relative to source/device, which has nothing to do w/ Atmos mixed Apple Music spatial tracks discussed here

(and it actually might be 3dof only, not sure since i've never listened to it)