Why are the oldest words in the world lost?

Some scripts, such as Egyptian hieroglyphs and cuneiform, were originally very complicated and were in the hands of priests and officials. People use simplified Chinese characters again and again. Over time, the original complex text prototype was not used or recognized, and the ancient Chinese characters were lost due to later wars, migration, national integration and other reasons. There is some truth in what is said upstairs, but isn't Oracle Bone Inscriptions also lost? It was not interpreted until modern times, but China culture has been passed down from generation to generation, so the writing has been passed down to this day. In contrast, other ancient civilizations are annihilated, and characters are more likely to be lost.