Earlier quoted context omitted.
If you can't tell the difference between the average LibriVox recording and the average commercial audio book, there is no way you can produce an Audible level of recording. Even if half the volunteering recorders and their gear were as good as those of the commercial offerings, just sitting and selecting those that are not good enough for publishing and those that require some re-recording is a massive extra work.
What is so special about Audible recordings that is unnattainable by Librivox? You mean sound quality? You mean some holy grail vocal mics? Or vocal talent? I don't get it.
I'm impressed by what librivox has achieved with just volunteers, but the production values are nowhere near as high as most books on audible.