I submit that Dunbar's Number[1] is a real thing, and that it informs the cognitive limitations of the human mind that inform nation-states.
This limitation also informs the popularity of Agile methodologies, if not their success.
And so perhaps the road to Lennon's "Imagine" is attained through an Agile mindset.
If the Iron Law of Oligarchy[2] doesn't win out first.
> Dunbar's number looks to me as something you can apply to village life, or bands of cavemen, but not any national structure from the past few hundred years.
I'd extend your few centuries to all of human history and argue that:
1) humans scale poorly
2) all efforts to scale them tend toward Towers of Babel
The counter-example is a military, where healthy young people can be coordinated at scale in an authoriterian system with a significant external threat.
The higher the center of gravity of the bureaucratic/aristocratic structure, and look at what the US has become in the last century, the greater the Tower of Babel risk.
The losers of the last Presidential election have declared a soft civil war.
Streamlined, simpler systems with higher-frequency, term-limited office-holders, can move toward Nirvana: redistributing power, not wealth.
Do you mind if I quote this attributed to you?
Cheers, mate.