Remember your first iPod?
Chances are you were forced to use something called iTunes. Now people do not think twice about iTunes.
But back then there was just no sensible reason, from the user's perspective, not to let a user add/remove music from an iPod without jumping through an additional hoop. People had to spend countless hours deciphering the protocol in order to build programs that could do what iTunes did: add/remove music.
Out of the box, the iPod was literally unusable without first installing some Apple software.
No matter how wonderful the design of an Apple device, the hoop jumping just becomes increasingly tiresome. I'm too tired to do the Apple dance.