In a lot of ways I thoroughly agree with you, but I do question the rationale behind your argument. Truth: NCAA Football is cyclical. All you have to do is look before the SEC domination. ACC used to be downright dirty, Big Ten has had its moments, and back in the day the Big 12 was what the SEC is now. However, I there is a lot I disagree with. I think everyone will agree that, until Saban retires, Alabama will be the pinnacle of SEC and possibly all of NCAAF. I firmly believe there will be competition when Urban starts to sign and breed the players he recruits. Florida's recruiting class is top 5 in pretty much every poll, and South Carolina will always be able to land solid recruits. Not to mention Georgia is one of the heaviest hitting recruiting states in the country. For that reason UGA will always be a force to reckon with.
That leaves one thing that it will come down to: player development. This is why I think the National Championships for years to come are between OSU and 'Bama. Saban and Urban show a unique ability not only to just recruit the best, but recruit the best that fit their system and turn them into the player they need them to become. I think we saw a good bit of that out of Charlie Strong this year with Teddy Bridgewater and a lot of other players on that Louisville squad. I disagree with you calling out Will Muschamp. He's shown the ability to develop players on the defensive side of the ball. Think about all those Texas defenses and remember how good UF's defense was this year (up until the played Louisville). Steve Spurrier has his fair share of guys who have gotten drafted as well (whether they've been successful or not is another story, but you don't get drafted by being a slouch at the college level)
Also, you said the SEC is going down then referenced UK and Tennessee o_O
So while I do agree with you, I haven't seen much from any other conference as a whole to tell you which one is next. I'd like to say the B1G, but with the exception of OSU and that team up north, I don't see any other team right now that is built to be a top 10 team over the next 5-10 years. They SEC's going to be the pinnacle conference for a while with 1-2 teams out of other major conferences making occasional appearances.