Vaporware product running into yield issues... I will assume Apple is testing multiple screen sizes and screen tech, if one screen has problem maybe they can try another or, god forbid they solve the problem and improve the yield. If Wong ton soup inc. can make 5" phones, why cant Apple?
I hope Apple will not use OLED, that would mean IGZO has some sort of major problem keeping it from being used. IGZO is a lot more "retina" friendly.