Apple has far more choices. Regardless of the benefits of any killer App, all the iOS users I know would not use a non iPhone eve if it was the only phone with AGI. So Apple is much more immune than say Android. Tons of Android users would happily jump ship to a bing phone if it appeared better on some criteria.
Apple always has two choices. Adapt or die. They always respond in the same way. They adapt to provide integrated end user benefits from emerging technologies, and expose those technologies to developers on their platforms.