What societies maintained prosperity without either collapsing or turning into, well, us?
That's like saying that because everyone has either died or is currently living there is nothing we can learn about health and longevity by looking at other people's lifestyles.
Not especially, since not only do civilizations not have hard limits on their persistence times like humans do, the very qualities which made certain civilizations particularly stable in their own time periods might cease to be viable in other ones (which is in some cases why they ended.)
People want to tell everything instead of telling the best 15 words. They want to learn everything instead of the best 15 words. In this thread, instead post the best 15-words from a book you've read recently (or anything else). It has to stand on its own. It's not a summary, the whole value needs to be contained in those words.
I'll start in the comments below.
(Voted by the Schelling study group as the best exercise of the meeting.)