The Sec is not slumping. The SEC is not being dethroned as the best conference in college football, but they are creating opportunities for other conferences. Have a look at how the SEC has succeeded over the past two decades, and you will find a pattern that ensures success for other conferences. You can take a look around football, and you will find that every conference is influenced by the SEC in some way. The SEC is merely a victim of its own success, and that is something that they should actually be proud of.
The coaching trees
The coaching trees in college football are loaded with guys who have been a part of the SEC.
You can find guys in every conference who used to be assistants in the SEC, and even the SEC has coaches who were once assistants in the conference. These coaches are creating better coaches under them, and those guys can get better jobs in other places. Look at someone like Charlie Strong. He has been the head coach at Louisville and Texas. Bobby Petrino was the offensive coordinator at Auburn, and he just had a kid win the Heisman Trophy at Louisville. Mark Dantonio was Nick Saban's assistant at Michigan State, and Jimbo Fisher was Saban's assistant at LSU. The list goes on and on.
The players
The players in the SEC are often so good that other players think they will never get to play. You get a kid like Lamar Jackson going to Louisville because he knows that he can play right away.
He does not want to wait his turn at a school like Georgia, and he will go to the place that will let him play right now. The SEC has spread out talent all over the country because these guys want to play right away. The conference has shot itself in the foot because it is so good, but that is what happens when you win almost every national title in the BCS era.
The coverage
More conferences in the country have gotten their own TV networks and gotten much bigger contracts with the networks. These conferences have more money than ever before to spend on facilities, and they can make their programs better with all the additions they make. It is not hard to see that these schools are all benefitting because of TV money, and they can all thank the SEC because the formula used to start the SEC Network was used to start every other regional network in the country.
Every conference wants to have a football game that feels like that Saturday game on CBS at 3:30, and they have created their own schedules to compete with the SEC. Guys will get seen on TV, and they do not have to only go to SEC schools to get exposure. They are so good they hurt their own conference.