_Those_ cameras are doomed because the iPhone does what they do, in many cases the iPhone does it better, and the iPhone is cheaper and smaller. At least an interchangeable lens camera will always have the feature that you can put a different lens on it. On the other hand people do make optics for the iPhone, too, so it's certainly not impossible for an "interchangeable lens iPhone" to exist in some way at some point.
I dunno, my non-interchangeable-lens camera (Canon SX40) has a whole range of features which are important to me and that the iPhone doesn't (and will never) have:
* 30x optical zoom
* optical image stabilization
* tripod mount
* flash hot shoe
* 58mm filter mount
* good ergonomics & no touchscreen
* RAW files
* scriptability of shooting e.g. for thunderstorms (camera triggered by lightning)