It’s always seemed like they bought Beats for the brand image. They were probably planning out Apple Music’s roll-out at the same time, and wanted Beats users to have a streaming service “branded” with it. (I don’t see Beats 1 going away ANY time soon, for example.) They probably saw an opportunity to get a leg up on everyone else, given they’re also the *only* streaming service at the moment with the money to make that kind of acquisition (except maybe Amazon, but…lmao Amazon Music)
Basically, you can only make things disappear so quickly before trend-following teens/young adults start to notice ;-)