I'm not sure there is a compelling reason to distribute final music pieces in 192kHz.
I can only speak from my own experiences, and I record and mix in 24/96 but for reasons that don't really relate to music distribution. When doing further processing, some plugins sound better with their algorithms taking 96k instead of 44k. Every plugin has been written with compromises. And I find I can push hires audio further in the digital domain before unpleasant artefacts arise.
It's very much like image processing. If you take a picture with a cheap basic 1 mega pixel camera and then play with the curves and sharpness, at a certain point smooth graduated colour becomes "posterised". If you take the shot with a DSLR (with 12 bits of each primary colour) then you can push the image a lot further before the posterisation occurs.
I have found the same occurs for audio. I can manipulate the sound with less artefacts when its hires. The plugins sound more transparent and smoother. I tend not to go above 96kHz because this effect is achieved at 96, and 192 (to my ears) sounds no better and I'd just have bigger files and more CPU load from the plugins processing the extra data.
The bandwidth of 96kHz is just short of 50kHz, so if as an added benefit I satisfy the one in a million Geoff Emerick's, then all the better.
But then once the final mix is rendered and no more processing needs to be done, ie for distribution, then this hires advantage seems moot. Maybe there is still some advantage for people or devices that may post process the sound digitally in some way, like a digital equaliser in your playback device, or something like that. But then again, that device could always upsample before processing.
I tend to use 88kHz if the final destination is intended to be CD, and 96kHz otherwise (so there is less aliasing when sample rate converting to 44kHz).
The reason I harp on about the bit depth is because in my experience that is where we are falling short. If I take my hires sources and convert to 44 or 48 with a high quality SRC I hear no difference at all. But when I change to 16 bit the difference is enormous. There is always a degredation. And it's never a good thing. It seems silly to just be throwing away that bit depth because of a 1982 format that people aren't even listening on anymore.
Also on the topic of SRCs, this site has some interesting comparison. For the record I do my SRC conversion with iZotope RX 64 bit SRC. http://src.infinitewave.ca/
So in conclusion, I want 24 bit tracks. If they're given to me as 44, 96, 192... whatever. As long as they're 24 bit. Enough with the 16 bit! :D