At some point through the chain, you have to have a change from a digital source (the music file on your computer) to an analog signal (that is pushing audio out of your headphones). If you are changing the headphone jack standard on the headphone end (changing it to a usb-c jack, for example) would simply be pushing the DAC into the headphone. Not only would this needlessly increase costs, it'd also remove the flexibility.
I personally think that more headphones should have the threaded 3.5mm jack on which you can adapt either the 1/4" jack or say, a usb-c or lightning adapter. This would effectively make it a permanent addition to your headphones without having to keep track of a separate dongle.
