Exactly! How the hell do you tease out what part of the profit was derived from the shape of the phone case and the arrangement of icons?!? Especially since the phone may not have sold, or sold as well, without those properties? Samsung's analogy about an 18-wheeler with an infringing cupholder is just absurd -- without A/B testing, there's no way to know whether buyers chose the 18-wheeler based on the cupholder or some other factor. But if the cupholder was the deciding factor (as, in actuality, it often is), then *all* of the profits were derived from that infringement.
Now I think design patents are problematic, especially when things are merely similar rather than indistinguishable, but I agree that this verdict was the worst possible outcome.