I assume you are implying that if the software can be updated, there would be no need for new hardware. Yet, for Apple, the opposite seems to be true :)
Apple is an edge case in so many ways that Android OEMs differ:
* Apple has a greater following of "must have the latest" consumers than most Android OEMs put together
* Apple makes money from the app store. Both selling apps and developers submitting apps that expose cool new features in iOS.
* Apple can release iOS updates that coincide with newer handsets but with software features only exposed in the newer hardware. Which also helps with the adoption of newer hardware.
Apple is smart -- they sell one version of their phone -- all the price differentiation comes from continuing to sell last years model (and the year before that, and so on).
Compare that to Samsung: they have high end phones, mid-range phones, and low-end phones in addition to last year's model.
Yeah, repeat and new customers buying your products because you support them and having existing customers recommended them to their friends and family.