Android is designed to be resolution independent. iOS isn't. There is a reason Apple choose 960x640 for the iPhone 4: It is exactly twice as wide and twice as tall as the pixel resolution on the earlier iPhones (480x320). Which means you just have to scale up each pixel into four.
I understand what happened before. Are we saying it could/should never change? iPhone's should forever be tied to a 3:2 aspect ratio? We should have media letterboxed on our devices forever?