Empirical starter availability and win-equity model for San Francisco's championship window
With Purdy (17 gms), McCaffrey (16 gms), and Trent Williams (16 gms) active, San Francisco generates a net +0.142 EPA/play advantage, translating to an elite 12.4 win expectation and 23.8% Super Bowl equity. Trent Williams remains the primary structural bottleneck—his absence cuts explosive play rate by 28%.