The argument is fine for listening to a finished product but those absolutes in the post have some hidden assumptions that don't hold in all real-world scenario

The argument is fine for listening to a finished product but those absolutes in the post have some hidden assumptions that don't hold in all real-world scenarios. That probably sounds like BS. Hear me out. A common practice for DJs is to use special decks to DJ from iPods, or other digital sources (eg. regular turntables with timecode vinyls operating a PC.) DJing involves playback speed adjustment when there is a BPM difference between the two tracks during a transition. 192kHz is overkill for basic DJing and you'd probably be fine in the vast majority of cases with 48kHz, but if the DJ is a turntablist (scratch etc.), you want all you can get when going from zero to target speed—which is happening constantly. It sounds awful when consumer-grade¹ audio is used. As for the ultrasonics, filtering is the answer in this scenario. It may be quite a good thing for these DJs (and their fans) that Apple is doing this. (I'm not under the impression that this is why they're doing it.) A lot of the music I listen to uses samples that are played at something like half speed, or tuned down at any rate. I tend to tune samples down by about a fifth myself. Point being: a lot of detail that would otherwise be present with higher samplerate source material goes missing. It doesn't help that tuning down like this dumps a good portion of the low end. There are also neat ways of exploiting nonlinearities from ultrasonic sources, which I use, but that's harder to describe. ¹not meant as a derogatory remark.