"hard to tell them apart, other than the shape of the home button at the bottom"
I always find this rather humorous. When the touchscreen is the dominant feature and the primary interface point, you're going to end up with a rectangle, possibly with a few hardware buttons sprinkled around the remainder. The only other real question is how thin can you make it.
Of course they all look about the same. Until someone comes out with a foldable screen, they're going to continue to look about the same. Once those foldable screens come out, they'll probably all look like mini portfolios.