The 49ers defense is great, undoubtedly the best in the NFL.
But it’s not historically great, and comparing it to the '85 Bears is hyperbole.
It’s not even as good as the 2000 Ravens or 2013 Seahawks as previously mentioned in this thread. (Those teams were historically great.)
But great, yes, no question. You have to have a great defense to win so much with a revolving door at QB.
I think older era defenses would mug the receivers down the field, forcing the quarterback to hold it longer, resulting in more sacks. Defenses were better back then because the league has since instituted rules that favor the offense, both rightly and wrongly.
By the same token, offenses are better today. Just that fact alone implies that defenses used to be better.
That too. The newer rules against contact mean today’s QBs can be confident throwing the ball to where they expect their receivers to be, whereas back in the 80s they had to wait to see their guy actually beat coverage.
Is it? They’re definitely on the short list, but is there a consensus that they’re better than, I don’t know, the Jets, the Broncos, Buffalo, Philly, even Dallas I guess?
I would say so, yes. Now, I don’t know that they are the consensus “best” (since that is somewhat subjective), but no other team that I can see is consistently at the top of rankings. Here are some samples:
Ranked #1:
Ranked #2 after the Bills:
https://www.lineups.com/nfl-team-rankings/defense
Ranked #2 after the Eagles:
Also Ranked #2 after the Eagles:
Ranked #1:
It seems like it’s between Philly, Buffalo, and SF, but SF is the only one consistently ranked high on everyone’s chart.
But again, they’re not dominant like the historic defenses were, which was my main point. They’re just really good, great, and it’s hard not to call them the best this year at this point.
And to this day that perfect ’72 Dolphins Team celebrates each season when the last undefeated team goes down. Like those ‘85 Bears did to Marino.
Those days of historic defenses are over. Doomsday. Purple People Eaters. No Name. Fearsome Foursome. Steel Curtain. Gone.
Dominant defenses today dominate differently because of rule changes and parity and salary constraints. The method of domination, and the amount of domination is different. It’s reduced. Because offenses are so potent.
It is a different game and different era today. A team can have a Ray Lewis or Nick Bosa or Aaron Donald or DeForest Buckner, etc, but that’ll be about it. Because of salary caps and parity they won’t have 8 of 11 Pro Bowlers or 4 HOFers like the ’76 Steelers did. You won’t see the ’85 Bears again. Similarly, the days of perennial powerhouses are gone. The days of perennial losers are gone.
The Aints for their first 20 years absolutely sucked. Archie Manning couldn’t help.
Between Super Bowl II and Super Bowl XXXI the Packers mostly sucked.
The Legion of Boom was less than a decade ago.
He brings up a good point, though. Free agency and the salary cap didn’t exist in '85, and there’s no way that Bears defense stays intact for multiple seasons in a salary cap / free agency era.
I think the Bills was the last great dynasty that can never be again, in terms of keeping so much talent year after year because you didn’t have to fit them under a salary cap and they were never allowed to become free agents.
Through that lens, the 2000 Ravens actually do pull a little closer to the ‘85 Bears. They only lasted a year partly (entirely?) because of the salary cap and free agency. Still not the Bears’ equal, though, IMO.
Yes but how often are there great defenses that have earned such monikers? The frequency has dropped dramatically in recent years.
It is rare, I agree absolutely. It’s a lot harder to pull off with salary caps and other attempts to enforce parity as well as new rules to promote scoring and protect QBs that hinder defenses.
It’s odd that points per game isn’t higher than it is. It’s not really all that different from, say, 1985.
It was significantly higher a couple of years ago - I think 2020 is the all time high water mark. But it was three points/team/game higher, not WAY higher. Given that almost every rule change has benefitted offense, I’m quite puzzled it’s not sky high.
Conventional wisdom is that defense always beats offense. Once it gets too lopsided, the league puts in new rule changes or emphasis to tilt it back in favor of the offense. But it’s only a matter of time until defense figures it out. Lather, rinse, repeat.
I don’t know how much that still holds true today, but maybe that could explain some of it. As one example, I think defenses have largely figured out the wildcat.
Consider the flip side. What was the last rule change or emphasis that made the defense’s job easier instead of harder? The only one I can think of is when they removed the force out, but that’s a niche benefit at best.
Exactly. The league has decided that fans like high-octane offensive football, and has spent the past 40+ years gradually changing the rules in ways that make things easier for offenses, and harder for defenses.
Offense sells tickets.
Defense wins championships.
I think a bit of it is because there is a tendency for many teams to focus more on running out the clock than scoring once there is a point disparity. If you’re up 21-3 late in the third quarter, you’re probably going to grind things out with the running game, make long and punishing drives that eat up the clock, and try to gas the defense. If you win a game 42-3 instead of 21-3 it doesn’t really help anyone but gamblers and/or fantasy football players.
But that does still leave open the question of why we don’t have more 40-37 shootout games. I don’t really know. I remember a few years ago we had some games like that and the announcers excitedly proclaimed that a new era of high-scoring football had arrived, but that didn’t happen.
I guess that maybe coaches and GMs realize that a solid defense is essential. And as the game evolves to favor the offense, they focus that much more on building a defense to compensate. And what you invest in defense will take away from offense. So they’re not really taking advantage, because they don’t want to rely on scoring a ton of points if you give up too much on the other side. It seems like a good defensive line is valued more than almost anything but a good QB these days.
Case in point… As a Seattle fan I’ve watched the Seahawks have a surprisingly good year. They’re poised to have a winning season and still have a chance for the playoffs when all expectations were that they’d crash without a star QB. They did not trade for a good name and insisted on starting a long-time backup in the starting role, who somehow has put himself near the top tier of QBs this year. Which is huge in a fluky year where 2/3 of teams have changed their starting QBs for one reason or another (injury, poor play). He has been relatively solid and a great leader.
Is there celebration? Are they building everything around this sudden unexpected strength? A little, but mostly there is a huge concern about the defense, particularly against the run. And all talk about improving the team isn’t about getting more weapons for Geno, it’s about getting better defensive players. Change the rules to make offense easier, and teams will just work that much harder to improve their defenses to compensate.
Teams know this and build as best they can toward it.
My hunch (which I’m not willing to research) is that the rule changes haven’t benefited offenses as a whole, but passing offenses specifically. So a lot of the points that used to be scored by running the ball are now simply scored by passing.
But passing gains more yards more quickly, so why aren’t scores higher? Two reasons:
In the context of replacing some of your running game with the passing game, those are quick passes that don’t require top level quarterback play to complete. Screens and drags and whatnot.
One thing I remember hearing from Mark Schlereth about that: When you run successfully you demoralize the defense. When you replace some of that with short passes, you mostly just piss the defense off. It may be the same yards or even more, but you’re not imposing your will on the other team like a good running game does.
You obviously haven’t watched many Bears games the last few years. 
The trend over time has been for the average drive to be more efficient, but for there to be fewer drives per game. In other words, the average offense hangs on to the ball a little longer every time they get it. Usually you’d think those two things would not entirely cancel out, and scoring would go up because, well, yards lead to points, but I think specifically what’s happening right now is that defenses are smart and they’ve adjusted to the new rules in such a way that they’re a little ahead of the offense. They’ve gone back to playing deep safeties and basically said OK, we’re not allowed to prevent completions, but we can force them to be short completions. So, completion percentages are high, the average drive lasts longer, but explosive scoring plays are more rare and over 60 minutes scores are down. It’s hard to have a shootout that’s just 10 yard play after 10 yard play.
Maybe the next thing that happens is the really good offenses adjust back, and start running the ball more against those two/three/four deep coverages.