Yes, the day will indeed come when the Sooners - by far the Big 12's flagship sports school - will say they've had their fill of Texas, just as Neb, Mizzou, and A&M have done. And the schools that acquiesced to the Longhorns and let them have their LHN just to stay will be left with nowhere to go.
Exactly how would you cure the LHN lesion?
Tornado Man is also misguided on a key point. NU and aggy were in the same corner as Texas relative to monetizing individual T3 networks but when ESPN offered the big dollars to Texas for LHN and NU/aggy could not get close to the same deals, they bolted like pussies.
The only way the "LHN lesion" get addressed in the near-term is by ESPN initiating a settlement with Texas to terminate the LHN contract. I don't see Texas initiating a settlement that would jeopardize a guaranteed annual revenue stream of ~$15M/yr through like 2032.
I am assuming that ESPN will try to somehow morph LHN/Texas into their ACC Network and at that point Texas will have decision to make. Be an extreme geographic outlier in the ACC and fully invested with ESPN or cash out on the LHN/ESPN deal, invest that money into equity with the PACN (The SEC and B10 are not options for the Texas), and partner with other B12 schools on a merger/alliance with the P12. If they choose the P12 route. The question then becomes how many B12 schools does Texas and the P12 want to partner with and whether OU wants to be included.