Two big things that I think contribute to this: 1) Most people are happy with good enough. To most people's ears, speaker quality makes a bigger difference tha

Two big things that I think contribute to this: 1) Most people are happy with good enough. To most people's ears, speaker quality makes a bigger difference than audio output, and people already settle there. Furthermore, when iTunes was a big deal it turned out people got accustomed to low bit rates and mediocre equipment and thought it sounded better than the good stuff, because it's how they expected their music to sound. 2) With most computing moving to laptops and then to mobile, people generally don't have a choice about the audio processing technology inside their computer.