Apple could have launched a 5.7-inch iPhone 6, but Jonathan Ive decided it was too big

One of the most interesting facts that The New Yorker is revealing is the existence of a 5.7-inch iPhone prototype that could have become an iPhone 6 (instead of the 5.5-inch iPhone 6 Plus). Reportedly, iPhone 6 prototypes were first created a few years ago, and, according to Ive, "the first one we really felt good about was a 5.7 [inch model]." Ive and his colleagues carried various prototype sizes for days and, eventually, the chief of Apple's design decided that 5.7 inches was "way too big." 5.6 inches was also too big, so they settled for a 5.5-inch iPhone 6 Plus to be released alongside the 4.7-inch model.
source: The New Yorker