There is no one deciding factor; that by now is clear with all the different firms taking an aim at the same bulls eye but through hundred different directions and hundred different projectiles. Mobile phones have gone through changes, and the development may be defined through many lenses. Painting the historical progression is not easy as each brush stroke will create its own explanation of the available landscape, which will be wholly plausible to the painter, though it may remain mystery to everyone else. For example I can talk about how the cell phone is a fashion accessory, or may be its form is what has changed, or it is all about creating a perception when it comes to marketing. I didn’t mention function because the data and voice connectivity are the lowest common denominator or "table stakes" and are a moot selling point, (unless the reputation of dropped calls becomes viral).
Thinking back when just owning the “brick” was fashionable getting a lighter one became hip, and then smaller was “in” and after that sleeker smoother sharper edges came and recently just owning one (of a certain brand) was trendy again. The problem with that paradigm is that one cannot really predict what will be fashionable and a device that is in major ways driven by technology becomes whimsical in its forecast, like predicting a pop diva’s next hit.
We can debate the form cycle (Brick, candybar, clamshell, slide, swivel, curved, square, round, oval) or function vs perception (clam is better than candybar or vice versa). In its own (short) era, riding on the technology of the time, each category met with its destination through varying tastes of consumers, be that due to any number of reasons such as demographics, location, cultures etc.
But there are other changes that interest me a lot more. Changes that result in cannibalization of function and form. Maybe cannibalization is not the right word here, I really mean convergence of functions, spread across devices, into one device. Almost every personal piece of hardware that used to cling to or hang from a persons, arms, legs, wrists necks have converged to one device. Pagers, Cameras, running GPSs, data entry, notepads, radios, portable TVs, gaming devices, calendars all now play together in one space. Substitution is one aspect but not only are all these different roles packed into one device, they are all connected. This is not just convergence, it is a connected convergence of function based on context and transfer of intelligence into one device.
