The point is to win the championship. The Super Bowl determines the champion.
The two best teams don't often play each other for the championship in any sport and haven't for decades now.
It's less so in football, but with with free agency, rivalries don't mean so much anymore. Without the same core of players year after year, the players themselves don't care about the rivalries, and that lack of feeling bleeds through. Also, because of that, rivalries wax and wane depending on the fortunes of the two teams involved. For example, the Raiders and Chiefs used to be an intense rivalry, but with how bad the Raiders have been for the last 15 years, it's not even close. When both the Cowboys and Redskins were good teams every year, that was a nice rivalry. Now, while the Cowboys have been relatively good most years and the Redskins' winning percentage acting like a yo-yo, it's not even close to the same.
I play air tambourine. Competitively.