Seattle has BY FAR the NFL's best defensive backfield.
They are what leads that defense and anyone including the DL in Seattle realize and openly admit that.
The DL can make plays because no one is ever really open.
Windows when they exist are very tight forcing risky throws.
Seattle plays downhill at you because they have zero fear of anything thrown 20+ yards.
The Seattle DL is very sound and unfairly deep but they are not the best DL in football.
Seattle's 44 sacks were solid but nothing like it's league leading 28 INT.
Carolina had 60 sacks and 20 INT. That's a team lead by it's DL.
There is little doubt there is a symbiotic relationship between pressure and coverage but being able to cover is hardly some meaningless skill that anyone can employ with good pressure. Again there is a reason you don't just rush 11. No matter how good the rush or how fast you have to cover. Same as you can't just drop 11. It takes both components to play defense.
I would argue one of the reasons their DB field looks so good is because of their front 7. they would even make us look good. not that their secondary is bad, they are pretty good across the board, but put them in our DB field and I am sure we get better, but not by much.
and if you saw the games seattle played, they don't give opposing QBs much time to throw. they come at you and they come fast and from all angles. you saw what happened to Payton and he likes to get rid of the ball in 2-3 seconds. they may not be the best, but they are deep. they remind me of the cowboys 90's line, which was 8 deep and were relentless and many of their interceptions was the result of pressure, ala what happened to Denver as you saw. so don't be so quick to give credit to the DBs for all the interceptions.
and I agree that there is a symbiotic relationship, but look at the steelers and GB and Giants when they won superbowls with their defenses. steelers front 7 set the tone. yes they had palumalu, but their CBs were average. their front 7 was relentless. same with GB, when they added Raji to the middle, their defense looked different. yes they had woodson, then average CBs. same with giants. their front 4 played out of this world, and helped them to two superbowls. when you don't have to blitz and can attack the QB with your front 5-6, then it helps your DB field not having to come up to help and drop into coverage and passing lanes.