Aside from the settled life, I think you need a certain size of population and interaction of towns. You are far less likely to find the genius who invents writing in a community of 40 or 50 people, perhaps 20 adults, than in communities with 10,000 or more. Also, where everyone knows everyone else, you just talk to each other. If you have large villages and towns engaged in commerce with neighbors, then you need to be able to record facts about transactions. Actually, it seems that early writings were primarily about numbers of different kinds of cattle and other commodities.
Regarding the disappearance of languages and people in the early middle east, did the formation of a one or two mile wide impact crater in the Iraq marshes around 4,000 years ago have anything to do with that???
Settled lives meant population increases, and increased family sizes, which led to a narrowing of the local genomes, and they have relatively more living descendants. Prosperity is how “bottlenecks” happen, rather than the reverse; and settled lives means agriculture. The earliest traces of post-hole structures are about 800,000 years old, while the earliest RC dated traces of agriculture known so far go back 14,000 years. Geometry grew out of keeping track of property lines, and recordkeeping for the same reason; simple numbering of things and names led to a literate class. Having large, well-fed, settled agricultural populations led to a need for common defense, standing armies, city-states, city walls, cults, the works. :’)