The SEC used to be all Alabama with Nick Saban, and then everyone else. Then Kirby Smart won two National Championships in a row, and the entire SEC began to improve. Now it's the most competitive conference in all of college football.
Georgia beating Alabama for Smart's first title got the attention of Oklahoma and Texas, who were extended an invitation soon after. That move set off massive realignment across all other conferences and teams shifting alliances at the drop of a hat. But the SEC stayed solid with the two new additions.