There was a rumor for a while Microsoft was gonna make a play for Rdio. I think Apple's belief is they can do what Rdio is doing themselves -- and with the iCloud streaming and everything now -- we might be getting close to that kind fo thing from iTunes.
I'm now using Rdio for about 99% of my music listening on a daily basis. I only use iTunes to keep track of podcasts, play pre-release albums, and as a media server for TV/Movies on my Apple TV. Besides that, it just kinda sits open most days. The Rdio catalog is just too perfect to add a bunch of shit to my queue - hit play - and forget about it.
What about when you're not at home?
Maybe I don't do as much music exploration as you do (well I'm sure I don't since my paying job is entirely non music related) but for me I can't fathom having to rely on a cellular connection in order to stream a song. Even with LTE now on the iP5 one day I'll be sitting at work and have full bars and the next I'll have no signal.
I think if we got to a point where our cellular networks were as strong as say, Japan's, I could see only using Rdio or Spotify for myself. As of now though the idea of relying on ATT in the subway sounds terrible.