You've heard the speculation, that the Big East (of course) and ACC end times are near, and four super-conferences will be here before we know it. I'm not here to add to that. Instead, let's just assume the speculation is true and also assume that the Big Four are smart in how they expand, with emphasis on maximizing TV viewership. But let's also assume the Big 12 (because of Texas) will be a bit less dynamic than the other three conferences. Those assumptions lead me to seeing the Big Four ending up more or less as the chart below shows.
I'll explain my reasoning conference by conference, starting with the Big Four. The narrow horizontal lines indicate how conference subdivisions might be worked out. Unless otherwise stated, I assume the conference schedule would involve playing everyone in your subdivision and one game with a team in the other subdivision, either your traditional rival or a random team. (But a Big 12 with 'only' 12 teams likely would play more games against the other sub-division.)
BYU and Boise are the best the Pac 12 can do, the possibility of invading Texas now over. The only quibble might be adding SDSU instead of Boise, but with California TV markets already dominated by the Pac 12's four California teams, adding SDSU has always been and always will be redundant. Boise though a small market is growing, and ‘only game in town' fan loyalty would likely spread throughout Idaho if the Broncos entered the Pac 12.
Again, I assume the movers and shakers will be smart, which includes tossing in the garbage whatever religious prejudice seems to motivate some Pac 12 Presidents' resistance to BYU's entry.
I bracket USC and UCLA because neither would accept being stuck in the less desirable (from their perspective) subdivision, but maybe if they switched off each year it would be acceptable.
The idea here is to create a Big Ten east subdivision that is attractive to national power Notre Dame. The Irish are the grand prize of the whole realignment whirligig, and most important they know it. So, by adding teams in two of Notre Dame's favorite markets (New York and Boston), and adding old rival Miami as well, and guaranteeing titanic matches against Penn State and Ohio State every year, that would be too enticing to pass up. Also, allowing Notre Dame to opt out of the required one game against the other subdivision means it will still have four non-conference games that it might be allowed to keep for itself and not consign to the Big Ten Network. Also, adding Notre Dame, Rutgers, and Boston College to Penn State will effectively establish the Big Ten as the conference Northeasterners care about if they do care about college football. If the Big Ten can then go ahead and provide excellent quality football to the New York and Boston areas, which I think it can, it might greatly increase the number of college football TV viewers in the region.
Purdue and Northwestern, and Indiana and Illinois, would switch subdivisions each year. No reason to reward any two of these (teams that don't bring much to the table) with permanent membership in the eastern subdivision.
Rumors I hear are that Texas opposes expansion, but they likely will have to go along with expansion to twelve, since there's too much money to pass up. Despite the rumors of Florida State romancing the Big 12, I figure the conference won't jump on that, partly because Texas will drag its feet and partly because Florida State just doesn't bring much in terms of TV viewers. We assume the ACC's top three TV viewership schools (relying on the excellent New York Times analysis published back in September) are maneuvering to escape the ACC as we speak, and that Clemson is the prize, with Virginia Tech not far behind:
But why would Clemson end up in the Big 12 when you would think it would rather be admitted to the SEC?
Because I figure the SEC has its eyes on bigger fish, which is to dominate Florida and Georgia TV sets. Assuming it will be smart about this, it will overcome Georgia and Florida reluctance to admit their in-state rivals. That small-mindedness could really damage the SEC, and it's about time Florida, for example, realizes that owning the Florida TV market - the TV sets in Orlando, Tampa, and Miami - is where the big money is. Grow the pie bigger - by bringing the two main Florida school into the SEC you grow yourself from number 9 into a top 5 or top 3 TV viewership school (while admittedly helping the Seminoles get into the top 20). A similar argument needs to win over Georgia on Georgia Tech entry.
ACC, MWC, CUSA
You can see that the ACC doesn't meet up with the apocalypse. It survives, but as the rough equivalent in football terms to the Mountain West Conference. But who knows, it still has some attractive schools. I could see Maryland and Virginia ‘maybe but I doubt it' being pulled into an 18-team Big Ten. North Carolina has a solid football fan base that, maybe, the SEC would want to pursue?
Not much more to say. The ACC and MWC will have a very outside chance of making the four-team college playoff, if that's the game they want to continue playing. The CUSA, I don't know, it may want to continue pursuing a cross-country coalition with the MWC?