It is interesting to make a connection between integrated solution and over-serving. To me, integration seems like a defense against feature sprawl and over-serving. Not saying they can't be disrupted, I just don't think it comes from their choice to integrate.

Disruption wouldn't come from Apple not covering all the use cases, but from making a really important use case harder to access than it should be. Amazon's Echo is a classic attack in this regard. If Amazon bets that Siri-like interfaces are important it should build a device that mostly does that, and does it better.

I don't see the smartphone as a whole being disrupted, especially by an open platform, since I still don't see a use case that Apple can't copy. If there was an innovators dilemma based attack it would need to radically simplify the interface. The problem is a multi-touch screen and display make the core value the diveristy of things the phone can do. A product cannot really collapse over some subset.