The most likely explanation is that we are treating the list too literally. This list is at least 4000 years old and we do not have the cultural context to understand what it's intent was
From what we gather, around 2300/2200 BCE the very first territorial empire known, the Akkadian empire rose and then fell. There's a great book about it called "The Age of Agade". Enheduanna, thought to be a daughter of one of the Akkadian rulers, is one of the oldest authors known! She is thought to have authored some poetry we've found from back then. After the Akkadian territorial polity fell, southern Mesopotamia fragmented into city states and that is when these 'king list' tablets are thought to date from.