Part of the mess the Big XII currently finds themselves in relates to NOT anticipating and NOT being in a position to act pro-actively to take advantage of opportunities.
The PAC, SEC, ACC, and B1G should be engaged in contingency planning NOW so they are in position to act on short notice, to invite the teams they want for the future,
rather than settle for the left-overs after the smarter better-positioned conference(s) make their moves.
That means identifying the schools they want NOW, ranking them, and discussing how various combinations of new teams fit into their division formats, etc.
There are two conferences that can call their shots. The Pac-12 isn't one of them. That is a very simple equation:
Good TV Market-but-not-necessarily-good-COLLEGE-TV-market
Geographic Isolation two time zones away (with apparently very little deference to Mountain TZ schools) from the action.
The ACC can't totally get there yet, but I'm convinced they can see the path.
Not sure OU has a ton of appeal to west coast viewer, but they are a much more valuable TV property to the networks than Washington State, Oregon State....
I wouldn't doubt OU's appeal over the schools you mention. It just so happens there are legal entanglements that prevent some possible "selective merger" that tries to take Washington without Washington State... and unless Phil Knight buys Corvallis to turn it into an athletic non-college side project, I wouldn't be surprised if the Oregon Legislature found roadblocks to put up.
The Pac-12 is probably going to cite the isolation and tell the country that the desire of other conferences to get to 16 doesn't apply out west. Simple reason: not sustainable. You'll get something like 2 16s and a 20 and a 12 and like it.