[dietrichepp]

You haven't done the math. Even home engineers won't have recordings with noise floors below -90 dBFS. That's just absurd. Double-blind tests have shown that trained listeners in ideal listening environments with high-end, calibrated equipment can't tell the difference between 44.1/16 and 88.2/24.

Audio engineers don't have to "deal" with the issues of downsampling and dithering. The DAW just does it. It's a solved problem. It's not even a button you have to press, it's all automatically set up for you these days. We know what algorithms to use: band-limited interpolation with dithering, possibly combined with noise shaping.

Headroom is a different issue, but even the sloppiest home engineer is going to take a look at the levels at some point. If they don't, they can just check the "normalize" checkbox when they bounce. Or they can just ignore it and leave it checked. They're still not going to give you files with noise floors below -90 dBFS, and therefore, there's still no point in giving you a 24-bit file.

Even for remixes, you're not getting any benefit, since the noise floor is above -90 dBFS anyway.

However... you want to work on a project together? Let's keep things 24-bit until the final mixdown.

[nerd_stuff]

I disagree that these things are, in the real world, "solved problems" and I'd rather have an unmastered raw track at 88/24 than a poorly mastered track at 44/16.

I don't disagree that CD quality basically maxes out the ear's natural capabilities, I don't think it's that easy to do.

For a remix I'd rather get a 24-bit stream than a 16-bit stream (that's really 15 bits) and has to be padded up to 24 anyway.