[exprL]

Part of the problem are the iOS design guidelines, which place the “back” button in the top-left corner (or did so in the past). A larger screen avoids the feeling of crowdedness, at the expense of reachability. If you rarely need to access the top part of your screen, the trade-off is usually at least acceptable if not worthwhile – less so with many iOS applications.

I mostly use my smart phone to browse the web, and I think one of the things Windows Phone got right was to place the navigation bar on the bottom (although I don't use Windows Phone, my phone does the same). Thus, unless there are controls at the absolute top of the page, I don't have a problem reaching anything (most native apps on my phone support gestures, which rely less on absolute finger placement).

[superdude]

"Back" is now a swipe from the left edge of screen to right.