IMO a school's home attendance is correlated to a team's FB value. It is interesting that the Top 4 MWC schools in avg attendance the last 5 real years (2018 to 2023 minus 2020), were the 4 schools selected. The only other MWC school over 21,500 was Air Force at 25,920.
The best remaining G5 schools over 25k and who I think the P12 will and should target next:
ECU 35,875
USF 34,281
Memphis 31,796
Navy 31,261
Army 29,522
App State 28,900
Air Force 25,920
UTSA 25,810
I think ECU, USF, Memphis, UTSA (startup program and large stadium in place already) are all no brainers. I think App State would be hurt by ECU. Do you really want 2 schools in NC? Then you have the 3 service academies. I think those would be nice adds. However if they were going that route, wouldn't they have taken Air Force over CSU? Also Army/Navy would be FB only.
Other possibilities IMO...
JMU- but they have a smaller stadium (24,169 avg since moving to FBS)
Temple- in Philly, easy for travel, pro stadium, good BBall history. But they have no fans. The team has stunk lately and no one shows up. Only avg 15,362 the last two years (22,023 for 2018-23 avg).
UConn- huge BBall program and near NYC/Boston. But only avg 20,116 per game. Although the last 2 years they are better at 23,377 per game. And would they really leave the Big East for this version of the P12? It would be funny if they got left behind again though.
Tulane- another easy in and out location. They have been pretty decent the last few years and attendance has reflected that (23,313 last 2 years). But for all of 2018-2023 they are only at 19,897 per game.
Do you think about a 2nd team in Texas (Rice, NT, Texas State, UTEP)? A 2nd in Florida (FAU)? Decent programs in smaller states (Troy, UAB, USM, Marshall, Jacksonville State)? Toledo? They are a good program and without midweek MACtion and better opponents they would likely get more people at games (19,884 avg). Plus they would have a recruiting advantage being in the P12 over the rest fo the Ohio MACs.
If you go to 6 from the East then I think they have to take ECU, USF, Memphis, UTSA, Tulane, JMU.