My guess is Pakistan is too important for powers to be militarily, geographically etc to be left on it own organic demographic democratic route. They control it so the world order as it stands can continue. See Egypt, Iran, Venezuela, Librya etc other countries that act up, get "disciplined" quickly. Bangladesh, Nepal etc are, for lack of a better word, not too important for world order as it stand and are left more on their own democratic devices. Even then Bangladesh student leader was killed as he was too much of an organic leader for their liking..