[user104658]

It's worth noting really that those early philosophers lived in what were mankind's first democracies. Different in many ways to modern ones but similar in concept, obviously. These civilisations were wealthy, and powerful, and comfortable enough for most... And they DID crumble. It's easy to see the progression of history through time as an upwards progression but it really isn't one. These societies (ancient Greeks, the Roman Empire) were FAR more advanced in many ways than Europe in feudal times... A thousand or more years later. It's worth remembering. In 500 years people (if there are any) may well be sat around pondering, "Isn't it weird that society was more advanced in 2000 than in 2250?"