I've never used anything but spotify on my iphones for years and this has never been an issue for me - i wouldn't have known or cared until reading these links.

This is true, but in practice on an iPhone the "default" music app didn't make a difference for me. I always had Spotify running (not necessarily playing, just the app open in the background) so when I pressed play it always played Spotify rather than Apple Music.

Then Apple is bad and Android is bad too. So the ethical choice is to buy neither. I'm not being facetious. I'm considering moving to pure AOSP based, Linux based, or just foregoing a smartphone entirely.