[naijaboiler]

80-100: my theory is as humans who lived hundreds of thousands of years in small hunter-gathering groups, there is a natural limit to interpersonal relationships we can manage on one-on-one level.

Any levels of social complexities beyond that has to rely on systems/traditions rather than direct interpersonal relationships.

[theIV]

Sounds similar to https://en.wikipedia.org/wiki/Dunbar%27s_number (in case you hadn't seen it before).