A marketing prof once told me that a lot of phone companies, Apple in specific, split their projects up into several releases as a form of planned obsolescence. You're more likely to find this in matured and established brand names because they have the power of goodwill to retain their market share whereas an up and coming company relies on being innovative in the sense of being early adopters of new, sometimes not fully tested, technology.

So for example, you see 3 iPhones being released in the span of 2 years. Those were likely 1 project released in a deliberately staggered manner so that "fanboys" "early movers" "brand loyal" (basically materialistic people who either don't understand or love being manipulated by corps) will pay for 1 project that a team worked on, 3 separate times.