fschmidt wrote
I think that success is the cause of failure for most societies.
It appears to be on a smaller scale, but the larger scale cause is climate. When climate allows individual success to turn into hedonism (through multiple circumstances that have to be intact, including a large enough population, civilization, technology), the decay will inevitably start, and we'll get the waves of cultures emerging and collapsing, until the larger scale waves in the climate are such that they don't allow individual success to turn into hedonism, for a while.