The way the NFL works, your enemy is your division first, then your conference, then the other conference. Therefore, when you make a trade, the last team you want to help out is somebody in your own conference. This has resulted in an interesting cycle of power where every ten years, each conference takes turns winning nearly all the superbowls of that decade.
In the 90’s, the AFC won 8 out of 10, while in the 90’s, the NFC won 7 out of 10.
So, my questions are:
Will the pendulum swing the other way in the next decade?
If so, which AFC teams will become dominant forces?
I think your premise is inherently flawed. You assume that one conference is top-to-bottom better than the other if the conference wins the majority of super bowls from that decade. This is simply not true.
The reason each conference has dominated a particular decade is because each time a conference had a successful decade, they had a dynasty.
So your premise doesn’t even hold up over the last four decades, the two most recent decades you selected as examples are hardly a pattern.
That said, New Orleans is the team of the 10s. They have deep young talent at the skill positions, a top QB entering his prime, one of the best young offensive minds in the league in Sean Payton, and one of the last remaining home field advantages in the NFL.
Trades aren’t common enough or generally high profile enough that they affect the whole league on that level. The balance of power shifts basically around which teams happen to be good at a particular moment. Some decades feature longer and more frequent runs by the teams of one conference over the other.
I think what happened in the 80s was, the Redskins and 49ers simultaneously established very successful models. The other teams in the NFC, notably the Giants, looked at the Redskins and decided THAT was the team to beat for the next decade, and built a team around the Redskins model. That model included enormous offensive and defensive linemen, and a punishing ground game.
When AFC teams came up against the Redskins, Giants and Bears in the Eighties, it was obvious they were woefully undersized by comparison. The Broncos’ defensive line looked scrawny when facing the Hawgs.