The expanded 17-game NFL regular season, combined with greater league parity and roster turnover, has made a perfect record extraordinarily difficult since the 2007 Patriots. No team has finished better than 15-2 in that era, and current win-total projections place even the strongest contenders—the Los Angeles Rams, Baltimore Ravens, and Seattle Seahawks—around 11–12 victories. Strength-of-schedule data shows most top clubs face multiple road tests against division rivals and playoff-caliber opponents, while injury reports and depth concerns further elevate the chance of at least one loss. Trader consensus at roughly 8–9% implied probability for any 17–0 season reflects these structural barriers rather than any single team’s shortcomings.