Fundamentally, that’s missing the point. In your initial post you said
If you ignore that, the rest of the discussion is meaningless†.
16 bits offers you 96db between the loudest sound you can record and the ineluctable quantization noise of any digital recording. With noise-shaping, it’s more like 100db over most of the audio band, rising sharply at high frequencies (which most of the denizens of this forum can’t hear anyway).
24 bits gives you 144db between the loudest sound you can record and the quantization noise. But that’s irrelevant: no one has yet created audio hardware with an SNR of anything close to 144db. Really good audio equipment will get you about`100db.
So there’s no point to pushing this one part of the audio chain way below that. 16 bits, with noise-shaping is already pushing the limits of what the rest of your gear can achieve.
† Maybe I should explain why it’s meaningless (since, apparently, that’s not obvious to you). The ratio between the loudest sound and silence is not 96db or 144db; its ∞ db. Decibels are a logarithmic scale, and log(0)= −∞.
But, in the real world, you never get absolute silence; there’s always some source of noise. So what’s relevant is the ratio between the loudest sound you can record and the noise.
WIth digital audio, one source of noise (quantization noise) is always present, so that’s what those number (96db and 144db represent).
As I’ve explained, beyond a certain bit depth, quantization noise just isn’t the relevant source of noise to consider.