Why long-range counterfactuals accumulate uncertainty

Why is a non-declining British Empire easier to model in the 1950s and early 1960s than later?

Because uncertainty compounds with distance from the divergence point, and later decades contain many more interacting butterfly effects.

A non-declining British Empire is easier to discuss in the 1950s and early 1960s than in later decades because every step farther from the historical empire introduces more butterfly effects. Procurement, political relationships, technology, and institutional requirements can no longer be changed one at a time while the rest of history remains fixed. Later claims must therefore become more conditional. The imagined timeline accumulates interacting consequences as it moves farther from its departure point.