TL;DR: capitalism.

I’ve put some thought into this and I don’t have a good answer other than because of how society is designed to keep us from doing it now.

Evolutionarily speaking, we are designed to thrive in smaller communities. It’s only in the more recent part of humanity that we seem to have moved away from that. I mean, there were still cities a long time ago, but within them were what could be thought of as smaller communities.

I myself am of European descent, but currently live in a place where there is a thriving native community and realizing that I sometimes have envy of some of their ways of life is what got me thinking.

For instance, in western society becoming elderly is almost seen as a problem, like a burden that needs to be “dealt” with. For them it is a station of respect and reverence. If an Elder walks down the street, they are taught to show respect and pay heed to their wisdom and guidance. If the rest of us are lucky, we can get a seniors discount at select stores by declaring they we are among the needy.

I’ve even went as far as researching communal living, intentional communities and cooperative housing, but I keep chickening out when it comes time to pull anything into action.

The idea of finding 4-6 like-minded families to share resources with and use our individual talents and skills to help each other really appeals to me. It makes sense to build resilience against harder times.

But to answer your question, smaller communities helping each other is against the capitalist ideal and is/will be thwarted at any scale by corporations and corporate influenced governments alike at every turn. So I guess that’s the most likely reason.