I.e., portable CD player/headphone system, you can reduce mass a lot more AND eliminate even more things that produce distortion and noise -
That is what world is going towards, or has already gone to. Eliminating CDs altogether. That eliminates CD players, too. It eliminates vibrations, maybe decreases need for isolation, and even decreases need for New Dark Matter. Oops! Did I just say that?
"Interconnects, speaker cables, digital cable, big power supplies."
Headphone cable is, effectively, a speaker cable. Thankfully, those have become obsolete, too.
As Michael Green correctly said many times (maybe not in exact words but to that effect), low-mass systems are what people of the future are going for.
Just ask any 16-year-old would they rather have red iPhone 11 with Airpods Pro, or Pass amplifier or two.