Maybe they actually do? For example, the 2017 version of the Nokia 3310, according to Nokia, can have calls of ~22h. And that's for a small 1300mAh battery. So

Maybe they actually do? For example, the 2017 version of the Nokia 3310, according to Nokia, can have calls of ~22h. And that's for a small 1300mAh battery. So it's technically possible to stream audio for a very long time. Maybe smartphones are doing the same in a very low-powered stand by mode?