New England Patriots quarterback Tom Brady follows through on a pass during an NFL football practice, Monday, July 30, 2018, at Gillette Stadium, in Foxborough, Mass. Credit: Steven Senne | AP

The New England Patriots’ dynasty, barreling toward the end of its second decade, will end, likely soon. There are several reasons. The primary reason is that everything ends, and most things in sports end long before – relative eons – what the Patriots have continued doing since 2001. The secondary reasons are ample. Tom Brady is 41, Bill Belichick is 66, Rob Gronkowski openly mulled retirement in the offseason and the future of their quarterback position, once entrenched in the dashing form of Jimmy Garoppolo, is a gaping void following his trade last year to the San Francisco 49ers.

Reports of palace intrigue and tension among Brady, Belichick and ownership last season amplified the examination of when and how the Patriots’ reign will halt. The Patriots have attempted, with varying degrees of success, to tamp down those concerns. Despite rumblings that the Patriots could break apart after their Super Bowl loss to the Philadelphia Eagles, the Brady-Belichick band is back, and there is no clear succession plan.

“The job of ownership is to keep continuity when you have something good,” owner Robert Kraft said in an interview this week on ESPN’s “SportsCenter.” “I think some people just make change for change’s sake, and I have a rule: We never break something down unless we can put something better in its place. And the Belichick-Brady combo has been pretty good.”

But the duo will not last forever, and its effectiveness may even wane before it expires. No one expects it will be this season – the Patriots are the Vegas favorite to win the Super Bowl and an overwhelming 3-to-1 favorite to win the AFC for a third consecutive season. The unexpected can happen, though, even to the Patriots. Whether the Patriots thrive as usual or struggle may depend on four factors.

Will anybody rush the passer? At an NFL training camp this week, one Pro Bowl defensive back considered a question about the Eagles’ offensive attack in last year’s Super Bowl and what the style – heavy on run-pass options plays – portended for the future of NFL offense. The player shrugged. “The Patriots didn’t really have that good of a defense,” he said.

And that was true. For all the (justified) angst over Malcolm Butler’s benching and internal friction, the Patriots walked off the field losers last January for a simpler reason: Their defense pretty much stunk, from start to finish. The Kansas City Chiefs dropped 42 points in the opener, and the Nick Foles-led Eagles hung 41 on them on the Super Bowl. In between, there were as many lowlights as highlights.

Longtime defensive coordinator Matt Patricia left to become the Detroit Lions head coach, and the Patriots are likely to more aggressive under linebackers coach Brian Flores, who leads the defense without the title of coordinator. The Patriots desperately need a better pass rush and playmakers.

Belichick has showered second-year defensive ends Deatrich Wise Jr. and Derek Rivers with praise, saying “nobody works harder than them.” Rivers, a third-round pick in 2017 who missed his entire rookie season recovering from a torn anterior cruciate ligament, is touted as a pass-rushing fiend. He – or some other Patriot – will have to be to avoid another long defensive season.

Will Brady stay fully healthy? Along with placing himself at the fore of the debate for best football player of all time, Brady has been a remarkably durable quarterback, a testament to his staggering commitment to fitness and strict diet. His regimen has allowed him to gain quickness and proficiency throwing deep passes into his early 40s. He has resisted and defied age better than any athlete in recent history.

Even for someone who shreds conventional aging curves, however, injuries diminish performance more as players age. During his MVP run last year, Brady’s only downturn came late in the season, after he showed up on the injury report with an Achilles’ injury. It affected him, particularly on deep passes and when throwing to receivers other than Gronkowski, a security blanket with a massive radius in which he is capable of catching passes.

Brady’s performance should be the least of New England’s worries. Despite his immense efforts, his age still makes him vulnerable to small ailments taking a toll.

Will the AFC be as bad as it looks? Quick, who is the second-best team in the AFC? The Pittsburgh Steelers, Jacksonville Jaguars, Houston Texans and Los Angeles Chargers figure to compete for the title, but all have significant flaws. While several NFC franchises spent the offseason loading up, no AFC contenders made obvious upgrades. The Patriots are in the easier conference to conquer, at least on paper.

Will the new pass catchers step up? Julian Edelman will miss four games on a performance-enhancing drug suspension, a topic that will make Brady storm out of a news conference if asked about it. (Edelman uses Brady’s nutrition and fitness guru Alex Guerrero, and Brady is touchy about the notion that Guerrero could have supplied whatever Edelman got busted for.)

The Patriots traded Brandin Cooks, their fastest downfield threat, to the Los Angeles Rams this offseason. Jordan Matthews, a big-name addition in the offseason, didn’t make it out of the first week of training camp before landing on injured reserve. Malcolm Mitchell, oft-injured but also frequently clutch in big games, was released earlier this week.

The amount of flux among New England’s receiving corps does not mean it is bereft of options. They signed veteran Eric Decker last week and added Kenny Britt in the offseason. They hope former first-round pick Phillip Dorsett has acclimated and can help replace Cooks’s speed on the outside in his second season in New England. Seventh-round rookie Braxton Barrios, out of Miami, is out of Patriots slot receiver central casting.

It’s hard to say exactly how the Patriots’ receiving unit will play out. But then, that’s true of the Patriots in general at this stage of their dynasty. They’re the best franchise in the NFL, and they’ll stay that way, until they’re not.