Wait, so she needs six apps to listen to her music? Mine's all in one place: Apple Music. All my ripped CDs, all of my classical music, all of my subscribed music, all of the music I buy from Bandcamp all ends up in one place and I can use it on all of my devices. Honestly, the subscription component of Apple Music isn't that important to me, but I've been building this digital library for twenty-five years and it is sizable, I don't want to go bobbing around from app to app to app. I want my stuff and I want it to work.
It's all an ecosystem, Spotify, Tidal, Amazon, etc. Each one has its corresponding streaming protocols (or they're borrowing someone else's) It shouldn't be a mystery why people who use one of these ecosystems is annoyed that theirs isn't included when a bunch of far less prevalent ones are. But, it is the choice of the manufacturer and one that may cost them sales, or not.