Beats Music -> Apple Music

Apple does care about its service business revenues, and I think they felt they needed to compete with Spotify, etc. instead of letting others slowly erode iTunes' share. This isn't about lock-in to iDevices -- Apple Music is also available on Windows, Android.

For Apple Beats Audio was a talent acquisition (eg: they got the founders, Trent Reznor and the like) for Apple Music, and a technology Acquisition (Beats streaming service and content is powering Apple Music) as well as buying a profitable accessories business.

Apple has great gross margins on computers because they have such operational excellence in building them, but still a Mac makes much less margin than headphones- at any price point along the quality curve.

Accessories are just generally really profitable.