Someone was pointing out how long the Egyptian and Chinese empires lasted, as an example of sustainable societies on the comments of one of the blogs I occasionally follow.

I thought about it a bit, and realized that they can not work for a model for a sustainable global or even national civilization in our current world for a number of reasons:
China and Egypt went through repeated periodic famines and various other upheavals, they both were made into part of more aggressively growing empires during Western Europe's age of colonization. They suffered this indignity due to their technological and military retardation.
They survived as long as they did largely because the culture, and technology were stagnant, and those in charge had control of key essentials for life (usually water).
Sustainable growth means population control - something very few modern countries do well. Western Civilization actually has a declining native born population over the past 20+ years or so- likely due to the best thing ever for population control; namely the education of women and empowerment of same (the pill helps less than education according to several studies IIRC).
China has also achieve low to no population growth but only through truly draconian and harsh methods.
Unfortunately those same 'western civilization' countries not only allow but are actively encouraging immigration without getting those immigrants to culturally integrate/merge with them. This is probably due to the need for economic "growth" for the moneyed interests (you cant pay a compounding interest debt if every 'dollar' is borrowed into interest without some form of "growth".) Thus these countries will eventually demographically return to population growth if they do not convert their immigrants culture (mind you it will be growth of a different culture inside their borders, not to dissimilar to what the Germanic tribes did inside Rome before its sack and fall). And China faces the high likelihood of internal revolution fed by their own draconian measures.
Having an aggressively advancing technological base *and* a sustainable infrastructure with controlled population growth is something I cant recall a successful historical example of. Please educate me if I am wrong.
But that (technological growth, population and resource use flat or minimal growth) is what we as a species specifically need globally to avoid future extinction on this planet...

Or we need to leave the planet and make use of space resources - but that has its own significant hurdles.