android phones are generally thicker than iPhone's so you can easily hide the jack behind the display.
the galaxy s6 has a bezel at the bottom just millimetres smaller than the iPhone 6. we can shed those same few mm as well on the iPhone or we can remove them completely.
the one plus two has almost the same size bottom bezel as the iPhone.
look at the lg g4. the headphone jack is as close to the edge as possible, giving enough room for the display.
so as you can see, either you shed a few mm or you thicken up the phone and hide it behind the display. and for reference, here are the internals of the iPhone 6. not much more you can do.