This question has been asked a thousand times in different ways and with different wording. Of course we all want the best possible sound quality; this doesn’t need debate. However, I think that the real question is how much does the listener rely on great sound in order to appreciate a great performance. How much of a “distraction” from the music are we willing to let the less than great sound be? Barring absolutely horrid recorded sound the musical merits of a great performance will shine through to one degree or another. Usually, to a great degree; that is the power of great music.
Personally, I think that many listeners are way to quick to declare a great recorded performance “unlistenable” because of less than great sound. I think that this is unfortunate. Of course, as bdp24 comments “it depends” on just how bad the sound is. However, I have found that there are relatively few recordings that do so much damage to the music that it keeps me from appreciating the brilliance of a great performance. Perhaps not fully, but close enough to know that I’m listening to a great artist.
It always comes down to this other way of asking the question (and, yes, we can be both, but….): are we a music lover first, or a sound lover first?