sec03 - Interesting suggestion. But for the B12, only Iowa State, Kansas, Kansas State and Missouri (from the SEC) would go to the B1G, while the Texas and Oklahoma schools are between the SEC and Pac-12.
Yes, highly suggestive as stated, and mass cooperation has never been the operating pattern. The BIG had the PAC12 backing out of a simple scheduling agreement/proposal because a couple of PAC12 schools later balked. There's also UConn sitting there if the B1G ever wanted another eastern or New England school. I believe the system shall be stuck with 5 so-called power conferences for a long time to come. There may be a few shifts/expansion 'additions' over time, but three (SEC, B1G, and PAC12) are not apt lose anybody. The ACC will probably not lose anyone else either, unless the Maryland lawsuit (not based on the current GoR) ends up, unexpectedly, to really damage the ACC to a vulnerable level. Even the B12 is indicating firmly what they now have shall be there for the long-term, relatively unchanged.
My point, there could be methodology to incrementally change the dynamics to allow broad action. But mass cooperation is not there, and certain schools and conferences are latched pretty firmly onto the status quo.