The picture?
This is the picture. In words that is, too lazy to draw some.
1. Almost all music recorded in 24 bits.
2. Conversion to 16 bits (without dither and noise shaping) chops off 8 bits of that. Let's be generous and say that half of that was noise anyway. So that leaves us with 4 bits thrown away. That represents 4*6 = 24 db increase in noise floor.
3. We are then told to use noise shaping to push that 24 db of extra noise to somewhere else. In 44.1 Khz, there is no place left to properly push that unless you cherish driving your tweeter and amp harder in 20 to 22 Khz. Best to increase the sample rate. But oh wait, we can't do that since you advocate sticking with 44.1.
But let's say we did use noise shaping. What that translates into is that we
took perfectly good 24 bit music file, added 24 bits of noise to it, and then applied a transformation to that noise. Why do we want to do that?
Why not just give the original 24 bit file to people who want it?
You see what the problem with the whole argument is? We had to jump through those hoops to get better performance out of CD which has fixed specification of 16/44.1.
With digital distribution, that restriction is gone, gone, gone. There remains no reason to apply that signal processing anymore unless you are trying to distribute on CD.
This is on top of the fact that
it is not up to you and I to apply noise shaping. It is up to the entire content production industry, vast majority of which have no background in signal processing and you will be lucky if you get dither for conversion of 24 to 16 let alone noise shaping. The whole concept of adding "noise" sounds like a bad thing to people without signal processing so it is not surprising that proper conversion is not assured whatsoever from 24 bit files.
So in summary, conversion to 16 bits from 24 bits is a form of lossy compression. Noise shaping makes it a perceptual technique so no different than lossy codecs. We no longer have a need for such a conversion.
Give the bloody 24 bit files and let's be done with it! No one has stipulated a single reason why it is good for me or anyone else to not have the option of getting 24 bits delivered to consumers.
That is how we get "done" with this conversation, not with hopes and dreams of the world all of a sudden deciding to noise shape dither all 24 biles. And even if they did, it would be a solution looking for a problem.
Really folks, physical formats that forced these things on us are gone. We have total freedom. Let's offer the consumer the
option to download music at originally captured rates. Technology and big companies are no longer a barrier to us doing so. Let's celebrate our newly found freedom! I know I am....
Edit: fixed typo of "bits" instead of "db."