I will be shocked if OU selects BIG as landing spot. It makes itself the new frontier, it migrates its recruiting north - when you want to be in a conference w/schools from Cali, TX, or FL, it moves to the rust belt, it moves away from its fanbase . Pac12 or SEC or stay.
I wouldn't. I think more and more OU fans dismiss the very arguments you make. OU would likely never give up the Red River rivalry, their football tradition is beyond indelible & they're within 2-6 hours drive distance of best recruiting grounds of Tx.
I've mentioned in previous posts a dream of OU, KU, UConn and UT to make the BIG (18) - such a setup would be the most formidable 1-2 punch in the biggest college sports (m. hoops & football).
UT to the BIG is a big what if, though the BIG nearly landed them back in the early 90s. Longhorns already travel up and down the I-35 corridor, going as far north as Ames, IA which is only 3 hours from Minneapolis, maybe less. But, that's the furthest north they go. WVa remains the biggest outlier for them, which can't be easy for Olympic sports. In the BIG they'd have to venture further east and north: PSU, Rutgers and Md.
But I have no idea at this point. OU could very well join the SEC.
I think the Pac12 ultimately sinks in as a really tough option for most current Big12 teams, too much geography coupled with time zone issues. Colorado proved to be the best candidate for the Pac12 due to the time zone, but that school has to deal with much more travel now. The closet road trip for Colorado fans in the Pac12 = just under 8 hours (Salt Lake City). That's pretty absurd. No other p5 conference has that minimum drive time, nearest opponent.