I'm really not sure where some of the other people replying to your comment are coming from. Forcing every human and animal you come across to listen to what you're listening to is selfish. Full stop. And not doing it costs $0, which preempts any question of resources.
But also, for all the reasons described, I just use transparency modes if I want that. That way nobody else has to hear my poor taste in music.
And on the few occasions where I've had no other option, it made so much more sense to set my phone to low volume and bring it close to my ear instead of holding it iut and maxing the volume.
And if I need to talk as well, many people don't know this, but there's a second smaller speaker on the opposite end of the phone, approximately one mouth-ear distance away from the microphone.