You see, the thing is...
For every single post like yours complaining about the audio quality... There is also a person out there who is unable to have a broadband internet connection (for whatever reason, geographical location, monetary, etc.) and the added sound file size, would add hours to their download time (if not days).
Personally, I have a cable modem and most downloads only take seconds (if that). But in my online gaming ventures, you would actually be surprised at just how many are still running dial up...
And, releasing different versions, or adding more download/install options is just too complicated (for the less computer savy crowd) and would probably would confuse most other users as well.
BUT, I do agree that at the end of the season, when (and if) they release the season on disc.
The hard copy should contain higher quality audio, simply because download size is not an issue with hard copies.
Continuing to include the subpar audio in the hard copies is just wrong, and them not taking the time to perform the necessary updates makes me wonder if they even have the ability to record uncompressed sound at all
(but i know they do, and thats what makes it even more unprofessional... it makes them look just plain lazy).