Because the size of thing currently is ridiculous. It's just too damn small. The least they could've done was made it an option. I don't want a wire going down my desk or a USB port taken up but I want a number pad with arrow keys that aren't miniscule. Really Apple? Is it that hard to just offer the option? They had the full keyboard on their previous generation wireless keyboard. Am I in the minority here or did people just give up on waiting for it? I was hoping they would change it when they updated the mouse from the Mighty Mouse to the Magic Mouse but all they did was make it run on two batteries instead of three. Awesome.