Many of the design concepts Apple tried are obvious as well, and have been implemented before. There's the squared-edge design, the round-edge design, and the multicolor front design. There's also an octogon-edge design (for some reason), which is non-obvious and would be noticeable if copied. All the other differences are on the back (where every vendor is different anyway) or in button placement (where every vendor is different anyway).
Apple went through 45 revisions quite possibly because they had never designed a phone before. And when they did settle on a design, they picked round edges and a screen that takes up most of the front minus room for a button and a speaker. That's hardly the most original design they put into concept. It's no surprise Samsung can easily make a smartphone casing, they could just pull out the specs from their Palm OS 4 devices.
The question is, why didn't Apple make the iPhone look like the iPod Mini? That was a seriously cool and original case. Now Nokia is making the same design.