Apple was beating then just fine at 4", with revenue and profits that exceed every Android vendor on Earth put together. Now, Apple is ready to annihilate the high end of the Android market. By this time next year, the most expensive Android you can get will be $300 and will run an obsolete version of Android on obsolete hardware. There just aren't going to be enough die-hard fandroids to keep the $500 flagship Android phones alive. Most people bought Android for size or price, now it will just be the latter.
iPhone 6 is going to make lots of money. Everyone going to buy it.