When the Buddha died, he asked the monks to take as their only teacher the Dhamma. Unfortunately, human nature being what it is, it is a lesson we forget over and over. Charismatic teachers arise, and we end up listening to them instead of following the simple words of the Buddha. Of course, the Buddha knew this would happen. Everything falls apart, even his own dispensation.
Once, the Dasārahās had a drum called Mudiṅga. Whenever Mudiṅga broke, they would repare it with a peg. Over time, the original head and frame of Mudiṅga completely disintegrated, and all that was left was a bunch of pegs.
In the future, there will be spiritual seekers that ignore my teachings, teachings that would lead them to liberation. They won’t apply themselves to the teachings. They won’t consider the teachings important.
Instead, they will listen to the witty words of poets, to the teachings of people outside the Dhamma. They will consider these things important and apply themselves to these teachings. And slowly the profound teachings of the Buddha will disappear.
So you should train in this way: listen the the Dhamma. It is profound and will lead to liberation. This is what is worth studying and mastering.
-Āṇi Sutta SN 20.7 (S ii 266)