Hard-core football fans remember decades by the teams that dominated them. In the 1960s Vince Lombardi's Green Bay Packers ruled the National Football League, winning five championships. The 1970s belonged to the Pittsburgh Steelers, with their four Super Bowl titles. Now, at the close of the 1980s, the N.F.L.'s team of the decade is clearly the San Francisco 49ers. Winners of seven divisional titles and three Super Bowls since 1981, they are favored on Jan. 28 to win their fourth Vince Lombardi Trophy in Super Bowl XXIV in New Orleans.
This season, despite a rash of injuries, the 49ers have remained...