How did the destruction of this cursed artifact affect this already highly warped world? Well apparently, it had no affect whatsoever, except that without the stone, most of the bad things that Sarah unleashed could never be fixed.
Or could they?
Since the wishing stone existed, who's to say that there weren't other magic items somewhere in the world? One of them could even fix their unfortunate situation. But where could they possibly find one? They don't just fall out of the sky.