Irreversible Accessibility Loss in Dissipative Systems Why Functional Persistence Does Not Guarantee Regenerative Futures

Many dissipative systems maintain local performance under repeated stress while progressively losing access to regenerative states. This paper introduces a structural framework to diagnose irreversible regime transitions based on the relative timing between forcing events and recovery processes. A normalized irreversibility index is defined and applied across physical, urban, and biological systems, revealing conditions under which functional persistence masks global accessibility collapse. The framework is diagnostic rather than predictive and provides an operational criterion to distinguish reversible, constrained, and irreversible regimes. The contribution provides an operational diagnostic for identifying irreversible regimes in systems that remain locally functional. Keywords Irreversibility; Accessibility of states; Dissipative systems; Structural thresholds; Regenerative limits; Systems theory