[What We Learned is returning for the 2021 N.F.L. season with a new writer and a new look.]

How dare any of us doubt a team coached by Mike Tomlin?

There are only a few guarantees in today’s N.F.L.: Tom Brady will eat his avocado ice cream and win Super Bowls. Jerry Jones will do something absurd to extend Dallas’s championship drought. And Mike Tomlin will keep his Pittsburgh Steelers in Super Bowl contention.