why does that only apply to physical buttons? The thing about the iPhone (and Android for the record) is that there are rather few interface commonalities betwe

why does that only apply to physical buttons? The thing about the iPhone (and Android for the record) is that there are rather few interface commonalities between apps. It seems that everyone is designing their own widgets, styles, and creating vastly different affordances. The apps are all very flashy, but user interaction can vary pretty significantly from app-to-app. I don't think that's necessarily a terrible thing. But why is that ok for the software (which is the bulk of the interface) and not the hardware?