I think the shifts in agriculture could definitely spark something, but robust political institutions and state capacity would have allowed them to weather the

I think the shifts in agriculture could definitely spark something, but robust political institutions and state capacity would have allowed them to weather the issues and adapt. Instead political fractures grew into much bigger problems bringing instability causing a downward spiral. Not to mention some of the biggest political shifts that happen around that era. The shift to the Late Roman empire is marked with a series of assassinations of the Emperor. Partially because of consolidation of the position's power and prestige. And in contrast other empires to the East and West organized and grew in power.