Space efficiency comes to mind as well on overall usability, can't stack anything above it (aside from storage shelves way above), kitchens are rarely big enough to store such a horizontal device, let alone in places where the $/m2 is high, like many city centers.
Also practical reasons, in horizontal config it's way harder to avoid my tomatoes getting squished by leftover casseroles, let alone having a small item roll around to the bottom never to be found again.
Also practical reasons, in horizontal config it's way harder to avoid my tomatoes getting squished by leftover casseroles, let alone having a small item roll around to the bottom never to be found again.