It is possible the $12K cables were just not as good as the $6K cables. It is also possible that the $12K cables exposed deeper issues with the Mac and B&W gear, or the original recording, or that the more expensive cables were just a poor match for that particular gear or weren’t broken in yet. In any case, your story just reinforces that cables sound different, and that it is important to try different cables in your system to get the right match for you and the kind of music that you prefer listening to.
PS - Full disclosure, I often cover my TV monitor when listening, but not always.
PS - Full disclosure, I often cover my TV monitor when listening, but not always.