Likely because humans have evolved to be able to know, remember and relate with ~150 people. Anything larger than that, requires organization and representation

Likely because humans have evolved to be able to know, remember and relate with ~150 people. Anything larger than that, requires organization and representation. https://en.wikipedia.org/wiki/Dunbar%27s_number https://en.wikipedia.org/wiki/Dunbar%27s_number