ESPN is the other voice in the room along with UT saying NO to TCU. They're advising against us because we don't expand their market.
This is a common fallacy. Conferences have their own motivations for expanding their footprint, but the TV networks don't guide them.
I know it makes a great conspiracy theory, but ESPN is already in every market, and they are covering every team located there. They already have BYU under contract, and they will probably have WVU, Louisville and Cincy under a long-term contract when this is all settled.
They are not sitting there saying "Don't take TCU. Take WVU or Louisville instead." They're already broadcasting WVU and Louisville's games, and will be broadcasting TCU's next year.
If this were true in any way, they would be encouraging UT to take Boise State or Air Force, two teams that draw national TV ratings but aren't broadcast on ESPN. That would actually add something to ESPN that they don't have.
Some people might argue that they are trying to keep NBC from getting the BE contract. Well, if that was ESPN's end game, and if they had so much sway in conference realignment, then they would just tell the Big 12 to add WVU, TCU, Louisville and/or Cincy and kill the entire conference in one fell swoop, thus preventing NBC from getting anything.