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All of the examples provided by the OP are technologies that were replaced by a convergent device. Pagers converged with the cell phone to make the flip phone. Flip phones converged with Blackberries to make the smartphone. iPhones are smartphones, and will some day converge with something else. It could converge with other mobile technology, such as wearables, or it could converge with a current technology which is currently less mobile.

I could see smartphones and laptops converging, and I think we're starting to see that with the continuity and handover features in iOS 8 and Yosemite. I could easily see displays someday advertising their presence to mobile devices. Once a user with a smartphone approached a large display, they could start using their smartphone as a desktop class PC with little fuss. I'm guessing Apple's device will still have a name similar to iPhone when this happens.
 
iPhones will die out when the whole smart phone market is completely dead. Now let's take look here. When is the smart phone market going to die?
 
Why do you assume that iPhone's will remain popular forever?

I don't see the fan base going any where. To most people it's not this whole big desion to stick with iPhone or not it's I need a new phone what did apple release. And they are in the apple ecosystem.
 
As much as I love Apple, nothing is forever, this world goes in cycles.

Dell, Blockbuster, Kodak, Yahoo, MySpace, Motorola, Sony, RIM, Microsoft, Facebook. All once dominant brands now slowly fading out of existence.
 
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