Nebraska is never ever coming back now that they are making full conf share.. Mizzou I think every single Mizzou b-ball fan wishes they never left big 12.. as for sec fball.. sec better hope Saban never retires bc when he does Bama won’t be the same.. if it weren’t for Saban and Georgia emergence the SEC might be 3rd in TV revenue..
There are enough big donors interested in keeping Bama on top that they would eventually be at a similar, but possibly slightly lower level, soon after Saban retires. It's not called the $EC for nothing.
Alabama football is very similar to Nebraska football, in that it's the only show in the state. The advantage for Alabama over Nebraksa is that they actually have football talent readily available in the region, and their success has occurred more consistently and within the last 20 years.
As for the SEC as a whole, I think they will always be good regardless of Bama's dominance. They have a ridiculous amount of talent down there, and a LOT of high quality programs devoted to football success. Bama, Georgia, Florida, LSU, A&M, even Tennessee. All of these programs spend a crap ton on football and have the financial backing, and fan support to do so. Even when a few of them are down, the rest are still solid to spectacular. The SEC is the top football brand for a good reason. They move the needle and they win games.