In the long arc of personal technology, the form a device takes often matters as much as what it can do — and Apple's first foldable, the iPhone Duo, has found early validation in that truth. A reader poll placed the wide foldable design decisively ahead of book-style and flip alternatives, suggesting Apple read the market correctly on its opening attempt. Yet preference and access are different things: a $2,000 price and a production ceiling of roughly 6 million units mean this particular vision of the future will arrive, at first, only for the few.