The answer to my question is "Because digital rights have completely ruined the concept of just owning a copy of a thing".
I can't just buy a copy and do what I want with it, I have to either continuously pay a subscription, pay for lots of stuff I dont need, or pay for a copy I can only view digitally at the publisher's leisure.
"Cant you just buy the music in a book?"
I can't exactly get the Animal Crossing New Horizons 5pm song for guitar and bass in a book at the moment.