There was an interesting podcast that talked about the last recorded use of hieroglyphic writing in the late Roman period. From the podcast, it seems like they just faded away as too cumbersome and being crowded out by more “modern” speech and writing.
Exactly! I assumed hieroglyphs were superseded by alphabetic writing.
Modern examples include when Turkiye changed its alphabet from Arabic to Roman, and kids today being unable to read script.
The use of cuneiform during the New Kingdom was widespread in the eastern Mediterranean and the Near East, as it was much more flexible and easier to use. It was used for diplomatic correspondence. The diplomatic archive of the late 18th Dynasty in Egypt was still setting there in the 19th century, and may be the largest ancient diplomatic archive known.
Hieroglyphs grew in number, and meanings of some are still obscure. That was probably the case during pharaonic times as well — a new sign was innovated, then the meaning was lost or the need to express it was either covered by more common sign or signs, or was itself lost.