See, I'd add digital music to the list of apples core competency, while they haven't stayed as relevant since streaming took off, you could make the argument that the initial success of the iphone could have been attributed to the fact that tons of people were locked into their music ecosystem via ipods, and the iphone was the only way to move said music to a phone.

Also note that apples services revenue, of which music is a part of, is large enough on its own to be a fortune 100 company.