The Buddha uses a simile of a cracked drum to illustrate that the profound teachings of the Tathāgata will disappear in the future as people lose interest in them.

Āṇi sutta - The Drum Peg

At Sāvatthi.

Bhikkhus, in the past, the Dasārahā had a kettle drum called the Summoner. When the Summoner became cracked, the Dasārahas inserted another peg. There came a time, bhikkhus, when the previous drum-frame of the Summoner disappeared, leaving only a framework of pegs.

So too, bhikkhus, in the future there will be bhikkhus who, when those discourses spoken by the Tathāgata that are profound, deep in meaning, supra-mundane, and connected with emptiness are being recited, will not listen, will not lend an ear, and will not apply their minds to understand them. They will not think those teachings should be learned or mastered.

But as for those discourses that are composed by poets, poetical, sweet sounding and well-worded, created by outsiders, spoken by disciples are being recited, they will listen, lend an ear, and apply their minds to understand them. They will think those teachings should be learned and mastered. Thus, bhikkhus, there will be the disappearance of those discourses spoken by the Tathāgata—profound, deep in meaning, supra-mundane, and connected with emptiness.

Therefore, bhikkhus, you should train yourselves thus: 'When those discourses spoken by the Tathāgata that are profound, deep in meaning, supra-mundane, and connected with emptiness are being recited, we will listen, lend an ear, and apply our minds to understand them. We will consider those teachings should be learned and mastered.' Thus you should train yourselves, bhikkhus."