It might also be because newer Bluetooth codecs being used. I think Apple doesn't publish a lot of documentation about it (or it isn't obvious, at least...)
Could be the case, but it is very obvious if someone is using Pros 1 or 2, the audio is really bad. This was honestly such a jump that I somehow wish my Pros 1 to break so I can get new ones :D Can't upgrade from a perfectly working set of headphones, although they are more than four years old and probably my 2nd most used device after the phone.
