It doesn't, but I've always figured this is probably a limitation of logisitics.
Because all DVD covers are in "portrait" mode and the screen of the 3000 is in "landscape" mode, 8 ends up being the optimal number per page. Since the shape of a DVD cover is "fixed," there's simply no logical way to arrange 7, 6, or 5 cover images. You can't go to 4 without turning the images sideways. You could go to 3 with a considerable amount of wasted space on the top and bottom, but 2 actually makes much better use of the space.
If you went with 2 or 3, the number of pages required in the remote would be vastly larger than DMX currently requires. And then it would take eons to scroll through a list of 300-400 dvds.
So, while your concern is valid, the solution would probably cause more headaches that the squinting that might be necessary by those of us with middle-aged eyes.