Hm, I'd argue it's not that obvious, otherwise companies would just try to miniaturize everything hoping that there's a market for it. Companies won't typically make this leap because it's fairly costly and their product manager may not get a bonus that year if the product is a flop. It's only obvious to you because everything is obvious in hindsight.
Whether something is obvious or not is irrelevant to this discussion.... the fact of the matter is, Apple created iOS, they didn't license it. The point I made was that Apple created that component, it didn't exist before. It was not off the shelf (as others were broadly claiming.)
Further, "obvious" is silly since nobody did it before them, and it is a post hoc ergo proctor hoc argument.
It doesn't really change much, though, as "make a [Surface|Lemur|Diamondpoint] handheld" is about as obvious a conceit as one can want.