Abundance is best understood as an energy and resource surplus, and surplus buys time that people reliably spend on culture: art, architecture, metalwork, ritual and shared story. The opening episode sets that thesis, previews five societies to come, and warns that the same surplus that built the cathedral also built the throne and the slave market under it.
Whether surplus causes civilization or merely permits it is increasingly qualified. Sahlins' picture of affluent foragers is also heavily critiqued, and Rapa Nui's pre-contact collapse is challenged by recent ancient DNA.