Your assumption is that studios are trying to achieve the ultimate playback quality and would do everything they could to achieve that. I don't believe that's a correct assumption, many productions are mastered in the nearfield on those little white-coned Yamaha speakers spaced about 4 feet apart
I went to a Kate Rusby concert and in the first half the sound was dreadful (far too bright and the vocals not audible). I told the man at the sound desk and it was fine in the second half. I mentioned this to the Technical Director of the theatre and he said most sound engineers had dodgy hearing because of over-exposure to loud volumes.
Nic P