Apple doesn't generally do what everyone wants. They do what they feel will deliver the best experience for their consumer. Yeah, larger screens have a benefit, but they're not as easy to use.
You have to keep in mind that after Steve's death a lot of things have changed, and Apple instantly showed signs that they would listen to the will of people. Best example of this is the HDMI connector on the rMBP (but yes, I know that it's a different thing, because the lack of HDMI was a real pain in most people's ass, but still only the minority of happy iPhone users feel that they would prefer a huge screen).