How do u listen and charge at the same time ?
Wireless ? If you say wireless is the future, you are not an audio enthusiast. Wireless has a long way to go
Built in DAC/amp integrated into headphones or buds ? You are not an audio enthusiast. It has a long way to go. Hell, even Dedicated portable players is having a hard time to put out quality audio at the power required for headphones and bud to sound properly. It is because power, power delivery, components, limited spaces, shielding from interferences....etc....etc.
*if you said it is possible to have good quality from integrated headphones DAC/amp built ?* then let me ask you, would it even be better to build this component in the phone as it house better battery and larger spaces ?