Interesting to read about Vocoders, frequency response and other excuses for phones that sound worse than a tin can on a string in a parking gargage underwater.
This still does not explain why performance is so much worse in the US and in particular New York City where God forbid we don't spend at least 5 hours a day, jabbering away on a speaker phone, while driving our SUVs with cupholders.
Oops I forgot - in the US, it really is all about the Benjamins.