The only thing that comes with a retail drive is, lets see, an instruction sheet that no one ever reads, and a disk with software you can download anywhere, and a pretty box. I don't know about you, but the last 2 or 3 drives I bought did not have any cables in the box. All of my cables came with my motherboard. And the 1 or 2 times they did come with cables, they were those really stiff cheap ones that I tossed into the trash anyway.
So I ask you, why would most people want to pay more for a retail boxed drive?