Thanks for reading, Laura, and for your thoughtful comments.

You're right. No one can manage 3000 relationships. But living in a structure shared by a community of that size, one would over time develop a nodding acquaintanceship with most of the rest, and each level (12 levels @ 250 residents) would become a neighborhood.

Quality of life would be quite high, for many reasons, so nearly all who live there would be invested in staying there and making it work, adding to the sense of neighbors being allies.

We're definitely on the same page here. Small communities are the best fit for H. Sapiens.