IMO the 4% rule is robust under continuation of economic assumptions:
1) Good Governance: Residents of the US have historically been lucky to live in one of the least corrupt regimes in the world's history. If we transition to a one-party state like Egypt, Russia, Turkey, China, etc. we can say goodbye to the concept of shareholders receiving a fair share of corporate profits.
2) Controlled Inflation: If we spent a decade or two with inflation above 10% like many of the world's residents do, it is unlikely that any portfolio or withdraw rate could help us escape poverty.
So instead of playing multidimensional chess, watch these factors and be prepared to move your money offshore like other people in the world do.