ITunes would not only take away 50% of the listeners, It might take away nearly 80-90% of the paying subscribers. Remember, most of the paying subscribers are from IPhone.
Secondly google music' ALL Access is a pandora like service on android. It is quite likely google would intergrate "All Access" into next version of android.
So then pandora would neither have android or iphone. Plus both the apple and google have users and music service so no one is going to buy pandora.
Sentiment: Strong Sell