Ancient Egyptian paid the price of being over-exclusive. Since the skill of writing (and reading) hieroglyphic, hieratic, and demotic writing was jealously guarded by a small, exclusive caste of scribes, once the Alexandrian and Roman conquests undermined the old Pharaonic regime and made Greek the new language and culture of the elite, that skill became largely redundant, and died out with the scribes.
The same is true of the Linear B pictographic script used in Greece until its adoption of the Canaanite script, and of cuneiform writing in Mesopotamia (whose exponents managed to keep on life support for some 800 years after Aramaic did the same).
The Canaanite script, on the other hand, which was created by an unknown Canaanite slave or trader in Egypt in the 1900s BC and then spread as a common-folk code of writing by all Canaanites, is the one that gave rise to Greek, Estruscan, Roman, Cyrillic, and virtually every other script this side of India.
The moral of the story: if you want something to survive, give it to everyone.
(Originally written in reply to a question at Quora.com)