This is literally said every single year.

I think the narrative was sort of born out of the ending of the Manning-Brady era cycle (obviously Brady is still playing and dominant but bear with me) and is somewhat based in nostalgia. You had QBs that had "their team" for the better part of a decade or more. Manning's Colts and Brady's Patriots battled for AFC supremacy, and then Big Ben's Steelers and that defense made their case for a couple of seasons (and still are). Those Chargers teams that were absolutely stacked to the heavens were around.

The NFC was a little less consistent, but teams like Favre's Packers were always at least in the playoff hunt aside from a couple of bad seasons in the mid 2000s, McNabb's Eagles, Hasselbeck's Seahawks, Romo's Cowboys, the Road Warrior Giants, and Brees' Saints were all in the mix for a while.

But you gotta remember that for all of those good teams, there were just as many shitty teams as there are today. It's not any different, it's just a narrative that we repeat every season.