Irreversible Viability Loss Under Locally Correct Interventions: A Systemic Limit of Performance-Oriented Design

In systemic practice, failure is commonly interpreted as a lack of performance, coordination, or optimisation. This article advances a different structural claim: systems may irreversibly lose viability while remaining locally correct, performant, and compliant with all known indicators. We formalise this phenomenon as irreversible viability loss under locally admissible interventions. Drawing on systemic theory, decision studies, and recent structural work on accessibility loss, we show that repeated locally rational actions can contract the global space of viable futures without producing immediate dysfunction. This result challenges indicator-driven governance and reframes sustainability, resilience, and organisational performance as problems of structural timing rather than optimisation. The article proposes a systemic diagnostic lens to identify such losses before observable failure occurs.