People will always want choices. And choices are a good thing as it keeps companies competitive. Some will choose Android because they are on service providers that the iPhone isn't on. Or because they like the UI better. Or because they like certain apps or WHATEVER the reason. Just like people will always choose the iPhone because of what it offers.
There's always going to be a reason to pick another phone. It's call personal preference.
I know, and I have no problem with choice. In fact, I'm the guy who has repeatedly said that no company will ever dominate the phone market the way the PC market was dominated. So I'm well aware that there will always be two or three primary choices in smart phones.
My point is that among the reasons picked Blackberrys or Android phones up until now was because of a perceived lack of functionality in the iPhone. So while price will be an ongoing decision maker, and service provider choice will be an ongoing decision maker, and user prejudice will always be a factor, lack of iPhone functionalilty will increasingly fade away as a dominant factor.