Lots of different reactions, only the first is really an author's reaction:
Given the volume of my sales at the moment, I'd just be happy they had them on the shelf at all!
Such an arrangement might help those like myself with a decision making disorder.
The objective is only achieved if the books are printed white on black. Only "black goes with everything".
The objective is only achieved if all your books are the same age - have the same amount of weathering - otherwise they are all different shades of fox.
Such an arrangement only suits those that were not brought up to treat their books with loving care; there's no way you can get books in and out of that shelf without damaging the pages.
...
I came to the sad realisation many years ago: my book shelf was never going to be tidy. Unless you wait for entire collections to be complete and buy all from the same edition/publication-run, nothing is going to sit smoothly on the shelf. When you found someone you like in mass-market paperback, do you throw that away and buy it again in trade paperback so it will match the next books you buy? Or worse still, an author you really love and grab the hardcovers, fat chance of ever picking up the earlier stuff in matching covers.