Once a master told two of his disciples to take care of his aching legs. Each one had to massage continuously each of his two legs. The two disciples bear strong dislike of each other. When one left for a break, the other broke with a stone the leg that the first one had massaged out of spite. The first one, angry at his doings, broke the other leg that the second one had massaged.
So are the Buddhist disciples. The scholars of Mahayana criticize the Hinayana, and vice-versa. Therefore, these two schools' scriptures of the Great Saint, run the risk to be both vanishing.