I am an industrial designer and have worked on cell phone. The camera sensor is usually the thickest component in the phone. In fact in the latest iterations of the iPhone, it sticks out by 1mm or so. This is because all of the other components are able to get thinner, except this one.

Now because it is so thick, it cannot be stacked on top of the battery which takes 90% or so of the surface of the phone. This leaves very few options: the top or the bottom. The bottom is out for obvious ergonomic reasons so that leaves the top. Now here is the thing: modern phones are PACKED with components. There is no room anywhere. This means that centering the camera would mean moving another large component and risking to have to grow the phone somewhere else.

The next explanation is an aesthetic one. If the designer decides to center the camera, then where is the flash going? To the left? to the right? Either way it will look unbalanced. The default position goes back to the upper left corner, just as in the previous 5 iterations of the phone.

Finally, moving the camera, beside detracting from the heritage, improve nothing and make the phone larger than needed would mean alienating millions of user who have been accustomed to this location over the past 10 years! As the saying goes, if it ain’t broke, don’t fix it…

See Questions On Quora