Consider how New Orleans has evolved in the last five weeks, since Drew Brees, its outstanding quarterback, injured his thumb. The Saints’ offense is not as productive without him, but with their rapacious defensive front, it does not need to be. Instead the Saints have relied on Teddy Bridgewater to fire short passes — according to the N.F.L.’s Next Gen Stats, his average throw traveled but 6 yards, trailing only the former Jets backup Luke Falk — and be an effective caretaker. Completing 70 percent of his passes, Bridgewater has led the Saints to five consecutive victories, reinforcing the value of a credible backup.

A more jarring transformation has occurred in Baltimore, where a franchise defined for years by its snarling defense now flaunts an electrifying young quarterback, Lamar Jackson. The Ravens weaponized him by designing an offense intended to make defenses wonder every play whether he will run, hand off or throw. Through Sunday, they had gained the most yards and recorded the most points.

Just behind Baltimore in scoring is New England, whose offensive limitations this year have been mitigated by the five touchdowns the Patriots have scored on returns. No team has mastered the art of reinvention the way the Patriots have. They have started the same quarterback, Brady, for almost two decades, and yet morph from season to season and, especially, from game to game.

These Patriots are bulldozing opponents not because of Brady — who according to Pro Football Reference commands an offense that has scored on 37.8 percent of its drives, 15th in the N.F.L. — but rather on the merits of the defense, which the advanced statistical website Football Outsiders deems the league’s second-best through six games since 1986. New England is allowing the fewest points per game (8.0) and limiting quarterbacks to a 42.6 passer rating, by far the lowest in the league.

It should be noted here that the Patriots’ defensive proficiency could be kind of, sort of connected to the atrocious offenses they’ve played so far: Four of their six opponents — Miami, Washington, Buffalo and the (Sam Darnold-less) Jets — entered Week 7 ranking among the bottom five in points scored.

The Dolphins and the Redskins are at a stage familiar to the Jets and the Bills, whose inability to unearth a franchise quarterback consigned them to years of mediocrity, and worse. The incalculable pressure to identify the next Brady, the next Brees, the next Jackson, compels teams to hang on to quarterbacks too long, hoping they fulfill their lofty draft status, or to select the wrong ones altogether.

There is a reason three such teams are languishing in the quarterback abyss. Tennessee, Tampa Bay and Cincinnati have made the playoffs a grand total of once in their last 24 combined seasons, going on 27. If history is any guide, they, unlike all the other teams barreling toward inevitability, won’t be joining them in the postseason.