The last time an AFC championship game did not feature Tom Brady, Peyton Manning, or Ben Roethlisberger was after the 2002 season. Lamar Jackson had just turned 6 years old. It was so long ago that the winning quarterback, Rich Gannon, has been retired for 16 years, and the Browns were in the playoffs. Brady, Manning, and Roethlisberger, incidentally, represented the AFC in the Super Bowl in all but one year since 2003—the lone year being when Joe Flacco filled the void. Sure, it’s stunning that Flacco is the one player who broke the stranglehold, but it’s even more stunning that three players monopolized an entire conference for nearly two decades.

That is over now. There are four quarterbacks left in the AFC playoffs. None of them has played in a Super Bowl, and one of them has played and lost in a conference title game. This is where you learn about quarterback talent and how to build around it. The NFL is in its 100th season, and in each of them, the shortest and easiest way to build a great team has been to have an elite quarterback. What we have learned from the AFC playoffs is that things are changing. Brady is out; Manning is retired, and Roethlisberger is injured. Flacco is Flacco. Deshaun Watson, Patrick Mahomes, Lamar Jackson, and Ryan Tannehill are here instead.

The old vs. young narrative is not that clean: Past Super Bowl participants Aaron Rodgers and Russell Wilson are both thriving on the other side of the bracket in the NFC, and Brady and Brees still have something left in the tank. But you cannot watch the first postseason of the new decade without knowing there is going to be a changing of the guard at quarterback. The Forever Quarterbacks, a group drafted in the early and mid-2000s, won Super Bowls and then changed the quarterback aging curve by thriving into advanced age more than any previous generation—now they’re cycling out. Eli Manning is likely going to retire, Philip Rivers is facing questions about his Chargers future, and Roethlisberger missed most of the 2019 season with an injury. Brees and Brady were both talented enough to guide their teams to the playoffs this year (and in Brady’s case win the Super Bowl last year), but their teams lost on the opening weekend. Brady will be sitting at home for the divisional round for the first time in a decade.

This weekend should not prompt an obituary for that entire generation—at least one or two members of it will keep thriving into the new decade. Brady already has said he’ll return to football next year and Brees’s Saints were one play away from advancing. Instead, the divisional round serves as an announcement for how the new generation will remake the sport. As Banner Society’s Spencer Hall pointed out, a good chunk of the most gifted college football passers ever has been concentrated in the past decade—players like Watson, Jackson, Baker Mayfield, and Mahomes. This, Hall said, is because of the spread offense, modern passing concepts, and players specializing in the position more. At the NFL level, it’s helped that coaches and executives stopped being so backward in their thinking about college quarterbacks. It’s been only in the past three years that the spread offense gained widespread acceptance in the pros.

Before last season, Oklahoma coach Lincoln Riley told me the Eagles-Patriots Super Bowl looked like a Big 12 game, and that the league was finally coming around on college schemes. In 2018. If any other industry were as bad at helping younger employees adapt as NFL teams have been at developing spread quarterbacks, there’d be some sort of reckoning. NFL teams mostly ignored that, though, and once the problem was solved, quickly moved on. The league’s general insistence on fitting square pegs into round holes in the previous decade cost it a generation of quarterbacks—and it probably helped some of the Forever Quarterbacks dominate longer than they should have. Those quarterbacks were at the helm for a massive passing boom, helped along by offense-friendly rule changes, that rewrote record books at the beginning of the past decade. Those same books are being rewritten by young quarterbacks now. The NFL’s failure to adapt is, mercifully, mostly over now. As to Riley’s point about the NFL looking like the Big 12: Titans quarterback Ryan Tannehill became the second-ever Big 12 QB to win a playoff game last week. The first one was Mahomes last year.

There are eight quarterbacks left in the playoffs, and aside from their general youth (Jackson is younger than LSU’s Joe Burrow), they have very little in common. This is highly instructive. They represent the era well precisely because there is no through line between them. They are paid differently, they play different styles, and their teams employ different team-building strategies around them. There are a few groupings: Three of the four remaining NFC teams have Mike Shanahan influences. Rodgers, Wilson, and Mahomes are all elite at completing passes deep. But you cannot look at the final eight passers and see any coherence. That is a good thing. There are no rules for quarterbacks. This is the lesson. There is no “pro style”; there is no prototype. There’s only talent and teams that know how to use it.

This is a good weekend to learn lessons about quarterbacks. Jackson is as dynamic a player as there is in the league. Mahomes is still among the greats, even if his numbers have dipped. FiveThirtyEight’s Josh Hermsmeyer made the point that Mahomes’s performance in stable metrics, like QBR inside the pocket, is generally on par with last season, while he’s dipped in unstable metrics such as red zone performance. The payoff here is that Mahomes is essentially as skilled as he was a year ago when he was the best player in football. Tannehill is not nearly as good a quarterback as the other three left in the AFC, but his team has surrounded him with playmakers, a creative offensive coordinator, and a running back who bullies people. Tannehill has been one of the top passers in the sport this year with a 117.5 rating.

Trends reverse themselves quickly in football—it’s possible some of these quarterbacks could be replaced by LSU’s Burrow, Alabama’s Tua Tagovailoa or, in two years, Clemson’s Trevor Lawrence. But what defines this year is a freshness not seen in the playoffs in years. The old generation is not done, but the new generation is making it very hard.

How much can we read into the Forever Quarterbacks’ struggles? Pro Football Focus’s Kevin Cole tackled the subject this week and said it’s hard to find statistical indicators of a gradual decline among the older set of passers, because the declines are not usually gradual: “Players don’t as much decline with age as become more likely to fall off of a cliff the older they are. The larger conclusion has been that it’s difficult to identify a lull in production from the beginning of the end—by the time you recognize that it’s over, it’s usually too late.” To write off Brees or Brady, or even a healthy Roethlisberger, is premature. Any of them could make a run in 2020. But it is impossible not to look at Jackson, Mahomes, Watson, or even Burrow as the elite passers of the future. They are here.

The best thing to have is a great, cheap quarterback and the second-best thing is a great, expensive quarterback. The gulf between those two things is pretty big—if you are the Chiefs or Ravens and have an MVP-level passer and get an extra $20 million to spend on other players, that is one of the biggest competitive advantages in the sport. But there’s a reason talented quarterbacks are expensive: They are typically worth an investment. It’s truer this year in the NFC: Kirk Cousins, Russell Wilson, Jimmy Garoppolo, and Aaron Rodgers all rank in the top 10 in quarterback salary cap hits, and all four are still alive in the playoffs. This is not to say they are the sole reason their teams are here—in fact, only Wilson could be considered a top-5 talent this year—but teams winning with high-priced quarterbacks is a teaching moment for a lot of bad general managers around the league who can’t.

If you’re looking for team-building lessons, start here: Paying good quarterbacks is an eventuality. So make it as painless as possible. No one loses because they paid a quarterback, they lose because they paid a quarterback then had no clue what to do afterward. The Chiefs’ general manager, Brett Veach, told me earlier this year that the team was planning Mahomes’s mega-extension since before he was a starter. The Packers and Niners gave their quarterbacks a lot of money upfront, but structured the deals to be able to spend on other players. The Packers gave Rodgers $66.9 million in cash in 2018. After an adjustment this season, they are scheduled to give him $7 million in cash in 2020, and his cap hit will be a manageable $21.5 million. Garoppolo, similarly, received $41.9 million in 2018 for a $37 million cap hit but has manageable cap numbers of at least $10 million less than that in every remaining year. All of these teams drafted well, which is essential. San Francisco’s Nick Bosa and George Kittle are star players on valuable rookie deals. So is Green Bay’s Jaire Alexander. But these teams still used free agency and trades wisely despite their big-money quarterbacks: Packers general manager Brian Gutekunst made two of the signings of the season in defenders Za’Darius Smith and Preston Smith, who helped remake Green Bay’s defense. San Francisco has augmented its roster with veterans like Richard Sherman and Emmanuel Sanders. Last year, the five highest-paid quarterbacks didn’t make the playoffs. This year there’s no such trend. The bargain-basement quarterbacks are here, but so, too, are the expensive ones, the lesson being that you can’t make Ryan Grigson–style excuses about paying your quarterback while building a team. You can win with any price tag.

The Vikings signed Cousins to the largest fully guaranteed contract in NFL history, a three-year $84 million deal, two years ago. They, too, have a stacked roster full of veterans. When I talked to general manager Rick Spielman earlier this year, he said he thinks continuity is one of the most important aspects of the sport. “Most of the guys we’ve signed, even the Linval Josephs of the world, their second year, they know the system better and they seem to thrive,” Spielman told me. “It’s almost like a rookie: You see this jump in their second year.” Cousins, in his second year with the team, has improved his yards per attempt by a full yard, has a rating eight points higher, and, crucially, made the playoffs. As the quarterback on a team with a talented receiving corps that includes Adam Thielen and Stefon Diggs, he helped engineer the upset of Brees’s Saints. He even resurrected a crowd-favorite catchphrase. He plays Garoppolo on Saturday, another quarterback who has never been this far in the playoffs. The NFC title game will have a new name. There’s a lot of those this year.

An earlier version of this piece misstated Rich Gannon’s opponent in the AFC championship game.