I always was wondered why the iOS navigation bar is placed at the top of the screen.
Navigation is a crucial of using an application, and some studies:
show us that the least used part of the screen is the top part, because of how people holds their cell phones.
Android uses a back button located at the bottom of the screen:
that is conveniently placed and useful when you are using apps like the browser, when you have to go back several times: Google something, open the link read it, isn't what user was looking for, hit the back button, open another link...
Is that a design flaw?
Should the navigation be placed where the user can use it better (at the bottom)?
iOS reachability seems like a partial solution, because they are generating another problem: Half of the screen becomes unusable when you activate it.