I would argue this is all the high-point of Apple's desktop hardware. The same drivers that run external DACs is the same they assign to their own internal hard

I would argue this is all the high-point of Apple's desktop hardware. The same drivers that run external DACs is the same they assign to their own internal hardware. This is likely just a holdover from their background of audio production tools in the aughts. For example, the Pro/Mac Macbook Pro supports 96Khz Audio at 32 Bits according to the same built in midi tool that you would also use to adjust the bitrates of external DACs. Sure my Onyx Artist 1 - 2 supports 24 bit at 192Khz...but the external headphone jack in the latest Macs also adds a fun bonus: A built in Amp for headphones over 300 Ohms. It's a weird add, but a wonderful one. (I do dislike that it is just a resistance detector that enables it though, my Planar HifiMan headphones are just under the cut so I have to drive them with an AMP for better sound.) Obviously, this all goes out the Window on iOS of course.