> it is surprisingly easy to achieve when a population recognizes a shared stake
Sure. But it takes work for anything larger than a small, close-knit community. I’m pushing back on the notion that this comes naturally and is a default state. It’s not, at least not relative to people naturally forming in and out groups.
The armchair commenters are probably folks who have never organized a group of people before outside a commercial context.
You might be treating "neighbor" too literally. People understand the global nature of the limits on resources and by extension the world economy better every year. The boundary of who shares 'stake' grows likewise.