Also the social network of people even just including the closest friends and family usually even in dense cities spreads out at least a few km.
Who do you think is going to maintain friendships across a few kilometres? Maybe the hardcore walkers, but the average person is just going to find new friends, just like they do now when distances become too great.
their entire supply chain would be much less (thermally/CO2/resource) efficient if we were to split theses factories to enable local production.
That's a feature. Have you seen how much Canadians bitch and moan about wealth inequality? Splitting up central operations into small, local operations is how you beat wealth inequality.
But I get it. Change is scary.