The Big 12 is okay now because their contracts are not up yet. When it comes time to renegotiate, that's when we will all find out if the Big 12 is still in good shape. My guess is that the Big 12 will be looking to expand before they start renegotiating in order to strengthen their negotiation position. If the Big 12 doesn't negotiate a good long term deal to follow up the current contract, then the conference is in trouble.
Pac 12 is not in trouble. They control every TV west of the Rockies. Having all of the major schools in the most populous state in the country is huge for revenue. While we may not stay up and watch here in the midwest, all of the people in the following top 30 metro areas are within the Pac 12 footprint:
Los Angeles (2)
Phoenix (11)
San Francisco - Oakland (12)
Riverside - San Bernardino (13)
Seattle (15)
San Diego (17)
Denver (19)
Portland (25)
Sacramento (27)
Las Vegas (28)
That's 10 areas in the top 30 where the Pac 12 is the dominant collegiate conference. That is huge financially. The Pac 12 has nothing to worry about. Their member schools have no interest in leaving for time zone reasons. They can expand if they want with no challengers and grab University of Nevada, BYU, Boise State, UNLV, San Diego State, etc. with no issue. They could not expand and not face any other challengers from that group.
The Big 12, in comparison, has Dallas - Fort Worth (4), Houston (5), and Kansas City (30). One of the reasons I advocate that the Big 12 add Cincinnati is that the Cincinnati Metro area is actually #29 right now. Although there are a lot of Ohio State fans there, Cincinnati has a huge following locally there in town. That's one of only two markets the Big 12 can tap into right now. The other, of course is Memphis (#42), right behind Oklahoma City.
West Virginia doesn't have an MSA in the top 100 - there are portions of West Virginia included in the Baltimore and Pittsburgh MSA's, but West Virginia itself does not have anything higher than #148. Iowa clocks in with Des Moines at #88. Wichita is #89. Tulsa is #54. Every other high ranked MSA is in Texas. For the Big 12 to ultimately hang on, the conference must eventually add Cincinnati and Memphis, or the conference will be pushed out of relevancy at some point.