Reversibility Eliminates the Autocatalytic Threshold: the critical catalysis of a reversible autocatalytic set vanishes with polymer length (c_c → 2 ln 2 / L → 0)

In random-catalysis models of autocatalytic sets (RAF), self-sustenance requires a finite catalytic threshold. Prebiotic bonds, however, are reversible. In a mean-field polymer model with reversible chemistry (ligation + cleavage) we show the critical catalysis c_c vanishes with maximum polymer length L as c_c → C/L → 0; for the standard availability threshold (θ=1/2), C = 2 ln 2 = ln 4 ≈ 1.386 (confirmed to 0.014%). The result is universal: c_c·L is independent of monomer alphabet size b, and across threshold definitions c_c·L = −ln(1−θ)/θ, so c_c→0 (1/L) for every θ. The irreversible (ligation-only) model retains a finite floor (1−√3/2≈0.134). We give a closed-form availability-front derivation and validate it by Monte-Carlo simulation. Implication: reversibility removes the need for a pre-existing efficient catalyst for the onset of self-sustaining chemistry, with a falsifiable 1/L signature. Part of the author's Information-Theoretic Origin-of-Life (ITOL) program. Reproducibility code (MIT) is included; the discovery procedure is proprietary and not required to reproduce any result (see NOTICE).