Personally, I have never really understood why, I guess as an example, phones like Samsung and iPhone need to keep creating more and more versions of the basically the same device. Each time a new device is created and released, they say its an even better version while in reality they've barely added anything and the only thing they've really changed is the way the consumer interfaces with it.  That's why newer versions of a phone are a waste a of materials and time and if a company still wants to change the way someone interfaces with it, they can just update the software of the device instead of having to build and design an entirely new phone. That's why newer phones are not needed and just wants.