Taking the parking garage analogy a bit farther, in a garage you would have just as easy a time finding your car (if not easier), if they would arrange the lots by car model.
But then parking would not be first-come-first serve. If you drove some obscure model, you might have to park a mile away (even if every other spot is available), which isn't too convenient. Plus, not all drivers, in fact most, don't have out-of-town manners and we'd be back to square one.
So too:
What's the difference? You can find them just as well if you sort them by size also.