Perception is a big part of it. If the Big 12 wants to be viewed as one of the big boys (which, financially, it clearly is) then it should make a move for established names rather than up and coming ones. The Big 12 doesn't want to look like a stepping stone conference.
No one is leaving the Pac-12, and the only team(s) that probably would consider leaving the ACC at some point are Louisville and FSU.
However, no one is moving for another nine years, and our TV contract will be up for renewal before FSU would be available to us. We have to have a reason for ESPN/Fox to reconfigure the deal prior to our next look in and potentially expand the GOR out beyond what the ACC currently has.
Look at it this way...
If we took Houston and Cincy now, got to 12, built them over the next nine years, extended the GOR by 2-3 years, we could potentially outlast the ACC. If, by that time, the money disparity is so great that FSU and/or Louisville feel compelled to leave, we have the following:
The ability to still expand to 14 teams like the Big Ten and SEC
Louisville would have travel partners in Cincy and WVU that would help rebuild some rivalries that were started in the Big East.
Florida State could potentially anchor an East Division that could include: FSU, WVU, Louisville, Cincy, TCU, Baylor, and Houston.
All four additions would be Tier 1 research institutions (which we are currently not). All have endowments over $600 million (which we do not have). All would be solid additions in basketball and baseball.
I think it would be best if we could stay at ten and potentially cherry pick ACC teams, but the problem there is that we have to re-up our deals before the ACC. If the Big 12 and the ACC are ripe for being ripped apart, being the second one to have your GOR expire is a good thing.
I can't imagine FSU fans hating a potential schedule of TCU, Baylor, Louisville, Cincy, Houston, WVU, and some combination of UT/OU/Tech/OSU/KSU/etc. more than the trash schedule that they currently have.
We're not going to be in a realistic position to pull Clemson, GT, Miami, etc. The pull of east coast academics is too strong. FSU and Louisville seem to be more inclined to follow the athletic budgets because they're more recent additions in the history of the conference, and they have no real tie to Tobacco Road. We may get two, at best.