They will never do that, this has the chance of doubling the memory currently needed to keep an inventory in check since you are now asking for a save to snapshot the location of each inventory item on the last position of each item before sorting. And then what? What happens if you sort, get an item, and then undo sort? Would that be possible or would the undo just pretend the last item wasn't there?

You might think it's easy, but it's far from it.