I disagree with what you are claiming here completely. Denver went through the same cyclical crap as the Ravens, Steelers, Colts and all of our other threats go through whereas we are the only constant over the last almost 15 years - except for the lost year of 2008 which was still pretty successful on its own. They were not a constant thorn in our sides as you like to point out.
Also, it is not disrespect to point out that Denver needs now things to go their way in games to be productive and play successful football. Sometimes they can force this by being a pretty good defense and sometimes they can't but continue to get bailed out by the bounce of footballs or other random factors. If both things dont happen they will lose games. Either way, what remains is that this is not a truly dominant team anymore because they don't have a consistently dependable offense in an age where most of the rules in the NFL are biased towards that.
They are on a downward slope to be a pretty good but not elite team like the Ravens of 2012+. Now whether Elway can fix that in FA is a different story but that's future talk.
What bothers me most about all of this is the media's need to label everything with hyperboles. First it was the Seattle defense that was the greatest thing ever, right now its Denver. Everything that happens now or comes next has to be even better and if it's not then we just invent/dig out some stats that will still give us our narrative because that's the idiotic society we live in. Denver's defense is nothing special in the context of history.. all of this has happened before and all of this will happen again.
Finally, let me emphasize again for clarity.. they are still a good team relative to the rest of the AFC but not on the same tier as we are right now.