If you compare the markets exactly then the real differentiator is simply that Google open-sourced Android into the phone business, but not into the music playe

If you compare the markets exactly then the real differentiator is simply that Google open-sourced Android into the phone business, but not into the music player business. I'm not sure if 'Google did it' is the real answer to your question or not, but it's interesting to note that competing on level ground with open source is extremely difficult - especially when that open source is backed by very heavy funding.