This is not true. The civilizations in ancient Egypt and Mesopotamia invented writing around the same time. Sure, hieratic or cursive hieroglyphs in ink on pap

This is not true. The civilizations in ancient Egypt and Mesopotamia invented writing around the same time. Sure, hieratic or cursive hieroglyphs in ink on papyrus is less durable than cuneiform impressed in clay (which more often than not, was not intentionally baked). But the Egyptians also carved and painted hieroglyphs in/on stone and that's plenty durable. Also, papyrus in Egypt survives much better than elsewhere because of the hot and dry climate. There's writing on papyrus that's 4,500 years old. The disagreement over whether writing was first invented in Egypt or Mesopotamia is mostly one of delineating writing and protowriting. There's plenty of examples in both cultures of markings from both sides of that divide, wherever it may actually lie.