On the weekend that Tom Brady returned from his four-game suspension, the paradox of the NFL was on display on the shores of Lake Erie.

The rest of the 31 teams want to know how the New England Patriots have managed to sustain their level of excellence during the modern era of free agency.

At the other end of the spectrum is Cleveland. The Browns have managed to remain buried near the bottom of the league since re-entering the NFL in 1999, after the original Browns bolted for Baltimore in 1995.

Green Bay, Seattle, Pittsburgh, Baltimore and Denver have been able to sustain championship contending teams. Everyone else? Not so much.

It appears the teams that played for the NFC championship last year — Carolina (1-3 before Monday night’s game) and Arizona (2-3) — are headed back to the pack much like the Falcons and the San Francisco 49ers did after playing in the NFC championship game in 2012.

The Falcons, off to a 4-1 start, have missed the playoffs for three seasons since coming up 10-yards short an NFC title in 2012. San Francisco has become a rudderless ship without the most vital winning ingredient: a quarterback.

Tampa Bay defensive coordinator (and ex-Falcons coach) Mike Smith was fond of saying “this is a quarterback driven league,” and therein lies a major factor to sustaining a championship-calibre team.

A rusty Brady demonstrated the difference he can make, throwing for 406 yards and three touchdowns against the hapless Browns in Sunday’s 33-13 pasting. The Browns, who have repeatedly failed to land a franchise quarterback, had to play a rookie, Charlie Whitehurst and Terrelle Pryor, a college quarterback who’s been converted to wide receiver.

“Once they get that timing down, Tom Brady is going to throw. I say he has an opportunity to throw for the most touchdowns in the NFL after missing four games,” former Falcons tight end and CBS analyst Tony Gonzalez said. “I give him 40 touchdowns on the year and an MVP-type season.”

In Brady’s absence, the Patriots “managed” their way through the suspension with Jimmy Garoppolo and Jacoby Brissett to a 3-1 record.

“Maybe the happiest guy in all of this is going to be Josh McDaniels, the offensive coordinator,” CBS analyst Boomer Esiason said. “He now has all of his toys. He’s got his entire playbook open and Tom will run it flawlessly as he always does.”

Where are the new challengers? After years of bottom feeding, the once powerful Oakland Raiders are showing signs of life. General manager Reggie McKenzie, a Ron Wolf disciple from Green Bay, has put a solid foundation in place for coach Jack Del Rio.

“I love the play-makers they have on both sides of the ball,” CBS analyst Bill Cowher said. “This team, the Oakland Raiders, is for real.”

But while the Raiders are moving up in the AFC, it appears the window is closing on the Cincinnati Bengals (2-3) after they qualified for the playoffs for five straight years. The team has had to juggle too many coordinators as Mike Zimmer, Jay Gruden, Hue Jackson have all left the team for head coach jobs over the past few seasons.

In Pittsburgh, the Steelers have long believed in continuity at the head coaching position. While the Browns are on their eighth head coach since 1999, the Steelers have had just three head coaches since 1969.

Pittsburgh coach Mike Tomlin, who has an elite quarterback, has them headed back in the right direction after the Steelers missed the playoffs for two straight seasons (2012, 2013).

“Well, he’s a really good coach, obviously,” ESPN’s Jon Gruden said. “And offensively, let’s be honest. The rubber meets the road in Pittsburgh with (quarterback Ben) Roethlisberger and the skill (position players) that they have. They’re going to win games regardless, as long as No. 7 stays healthy and they surround him with the arsenal that they have.”

The Bengals, in the meantime, were defeated by rookie quarterback Dak Prescott and the Dallas Cowboys on Sunday.

“The 2016 Bengals don’t look anything like the 2015 Bengals,” Dayton-Cincinnati radio personality Chick Ludwig wrote on his Facebook page. “They are absolutely dominated (Sunday) in the trenches by Dallas’ overpowering offensive line and the Cowboys’ underrated defensive line. … The Bengals are 2-3 and will be lucky to finish .500.”

In the NFC, the Minnesota Vikings, the last undefeated team in the league, appears to at the start of championship level run. They dethroned the Packers in the NFC North last season and have withstood a brutal rash of season-ending injuries early in 2016.

Without quarterback Teddy Bridgewater and running back Adrian Peterson, the Vikings have continued to surge.

“There was never a panic with any of those things (injuries),” Vikings safety Harrison Smith said. “There was just a real level of confidence. Not a fake bravado or whatever, but there was a real trust with everybody in the room and just the desire to go play and go win.”

Without their stars, the Vikings appear to be legitimate.

“They have three budding young stars on defense,” CBS analyst Bart Scott said. “And finally the Minnesota Vikings are transferring from an Adrian Peterson-Teddy Bridgewater team to a defensive team. This team is stifling. They got Cam Newton (eight sacks), Aaron Rodgers (five), and (the New York Giants’) Eli (Manning) wanted no parts of it (last week). They’ve held opponents to only 20 points in the second half and they beat you down, man. They’re fast and physical.”

Teams are in constant search of the coach with the winning touch and the quarterback who can dominate games. There were seven teams that opened the season with new starters at quarterback.

“But, look, there are so many different head coaches every year and different coordinators, you might as well have new quarterbacks,” Gruden said. “It’s an incredible league right now, the way that it churns out new talent at quarterback, offensive coordinator and head coach. You don’t get very long to establish yourself.”