Irreducible Latency and the Instability of Galactic Restraint: A Structural Filter on the Late-Time Fermi Paradox

This paper formalizes finite communication speed as a structural selection pressure on large-scale technological systems. It distinguishes origin, propagation, and coordination regimes and demonstrates that persistent galaxy-scale coordination becomes unstable when replication timescales are shorter than interstellar information latency. A minimal exportability trade model is introduced to show how coordination-dependent architectures are structurally suppressed under delayed feedback and superlinear enforcement overhead. The combined latency–exportability filter predicts the absence of large-scale coherence in technosignatures rather than the absence of technological activity. This work forms a foundational component of the Deep-Time Structural Constraints series.