Apple will probably buy it and kill it. It's their business model.
You mean like Pandora buying Rdio? Yeah, companies often buy businesses ( even failing businesses) so they can access trademarks, people with specific skills, etc. It is definitely something Apple has done, but they are far from being alone in those pursuits.
Pandora's price, according to articles, is down 60 percent since October and is down to 1.8 billion from 7 billion two years ago. They are dying on their own without Apple killing them directly. Keep in mind, Pandora is the one actively shopping for buyers.
If Apple buys them, it won't be because they want to kill a competitor. They would be better off buying Spotify (another business currently losing money at an accelerated rate) if that was their goal. If they bought Pandora it would be for the people/knowledge, great music engine technology, trademarks, etc.
I think Pandora would offer more value to Microsoft, but then again, I am not sure what Microsoft would bring to the table to pull Pandora or Rdio back up, but Cortana might be an avenue if they could figure out how to get it to work on iOS and/or Android.