I agree, and even feel more strongly about it. Even if you don't stumble, it's hard to compete with Google and Apple at this point, because they have their services tightly tied in with their other products. Buy an iPhone (hell, or even a laptop or tablet), and Apple Music is integrated out of the box. Same with Google Music.
Personally I think Spotify is doomed to fail (for various definitions of "fail") for the same reason. There are some people who want their music decoupled from their OS/hardware, but I think there are so many more than want it to "just work", and I think that Apple & Google have a better shot at that than anyone else, at this point.
Wouldn't the only reason there being limited choice be because of the way music deals are structured? I'm not familiar enough with how those work but having a mismatch of payouts / winning labels vs listeners would be a problem.
Being unable to add local tracks like I can with spotify is a killer feature that was missing as well.
My experience with Rdio was one of frustration. Their desktop player was buggy and frequently failed to play anything at all. When it did work, I found the consistency of the music catalog to be unreliable. One week they'd have the license to an album I wanted to listen-to, and then they'd lose it, and I couldn't listen to that anymore. I'm not sure what factors were at-play on their end to cause that to happen, but it was a horrible experience for he listener.
I wanted to like Rdio, but they failed at the basics in my experience.