Itâ€™s not that Apple didnâ€™t try a bunch of different form factors â€” itâ€™s that they tried them internally, figured out which one was best, and only shipped that one.
More internal stuff, according to Adrian Slywotzky, Harvard Business Review:
We are all mesmerized by Apple’s beautiful design, from device to screen, to the packaging itself. We see what the magicians want us to see. What we don’t see is the 18 months of negotiating with the music companies. Nor the three years of teaching the supply chain that the Macbook Air had to be really thin, really light, and really enduring (10-hour battery). When those improvements intersected with the iPhone’s great screen technology, the iPad (that glorious Air/iPhone hybrid) exploded.
That great screen technology, the 3.5-inch Retina Display manufactured by LG Display, also took a long time to perfect.