Exportability Filtering as a Post-Maturity Evolutionary Constraint on Galactic Expansion

This paper introduces exportability filtering as a post-maturity evolutionary constraint on galactic expansion. After technological capability is achieved, lineages may differentiate rapidly and propagate under irreversible separation. In such regimes, long-term expansion success depends on isolation robustness rather than centralized coordination. A minimal coordination–exportability trade model is developed to show that strategies relying heavily on enforcement and shared infrastructure can experience suppressed effective propagation when coordination costs scale superlinearly and exportability gains saturate. Under broad parameter conditions, robustness-dominant strategies outcompete speed-dominant ones. The resulting expansion geometry is characterized by distributed, weakly correlated occupation rather than synchronized galaxy-scale coherence. This work forms a propagation-layer component of the Deep-Time Structural Constraints series.