I don't know. Considering ROI for football national broadcasts, if we look at Pacific and Mountain Time Zones, let's say you have the following in a new CFB league which separates from the NCAA:
USC, UCLA, Oregon, Stanford, Washington, Arizona, BYU and Colorado.
That's an 8-team division and while there may be substitutes like Cal, Utah or ASU which could do relatively equal to their alternatives there's no fiscal reason to go beyond 8 because 2 from the same market doesn't add value unless we're talking about LA with a population larger than like 45 states. It captures every major market.
So we're at 8.
FL and TX are the only other states which command more than 2 - and I still don't think you need more than 3 in any. UT, aTm & TCU hit the 3 Texas population centers. Same for UF, FSU & Miami in Florida.
That's another 6 for 14 total.
As far as states with populations which justify more than 1, the only other is NY and that's not a good CFB market.
Then, CFB is different from pro because it doesn't have to be in the big city and there's a valid argument that it actually is more of a hindrance than help to be in one. So you look at which schools can represent a state, region or national audience.
From the B1G region, you want Minnesota, Wisconsin, Nebraska, Iowa, Illinois, Michigan, Ohio State, Penn State, Maryland and Rutgers. You add Notre Dame to this and you secure both Chicagoland and IN along with national marquee. So you don't need Northwestern, Purdue, Indiana or Michigan State since they won't increase ROI.
That adds 11 for 25 total.
From SEC country (beyond FL and TX which had already been addressed), you want Missouri, Arkansas, Tennessee, LSU, Kentucky, Ole Miss, Georgia and Alabama plus Auburn being such a marquee national brand that you take 2 from AL despite not needing based on population & markets.
That adds another 9 for 34 total.
From the ACC in addition to the 2 FL schools, Clemson is the choice over South Carolina for that state, plus you want to have North Carolina and Virginia.
That's another 3 for 37 total.
From the Big 12, in addition to what I mentioned in the PTZ & MTZ and TCU, you would want Kansas.
That's 1 more for 38.
If you go to 40, you could make the case that New England is too large of a market to ignore and that while none of the programs (Boston College, Syracuse and UConn) are national draws you still need to be in the region. I'd pick UConn since it has the highest engagement due to its basketball programs, ESPN in its backyard and can do a bit to get more of a foot in the door in that lucrative NYC market which Rutgers doesn't come close to owning.
We're now at 39.
For #40, I think the best cases can be made for GA Tech (GA is massive), Michigan State and South Carolina. With the latter 2, you don't fill a 75k+ stadium unless you have a very engaged fan base.
Take all 3 and you're at 42.
Beyond that, maybe Indiana as a flagship (since Notre Dame isn't really that state's school), West Virginia to represent a region and its passionate fans, Pitt for its history and regional clout, etc.
It's hard to get to 48 (even if I brain farted and missed a couple as I was going through this) and I have trouble finding an argument to go beyond 48. Beyond 48 doesn't seem accretive to ROI and maintaining fan engagement across the country.