The ancient Athenians couldn’t even manage pure democracy in a city state where everyone knew each other. It degenerated into demagoguery and civil war with Sparta, followed by invasion and destruction at the hands of the erstwhile-vanquished Persians.
You are correct! I myself see the fall of Rome and Greece happening today in my nation and nations of Free Europe. I am not optimistic based on history.
Herodotus implies there were 30,000 adult male citizens in Athens in 499. That suggests a citizen population around 120,000. There were also resident aliens and an unknown number of slaves. It's unlikely that everyone knew everyone else. Perhaps citizens knew the other citizens of their deme (village) at least by sight. But some citizens who lived a long way from Athens may have rarely come to the city.