Actually, while Texas wouldn't budge, Larry Scott had 4 schools lined up to go to to the Pac-12 (I think it was OU, OSU, TAMU, and Tech) but got vetoed by the Pac-12 school presidents.
That is correct.
If memory serves, without Texas, the Pac was not going to bring in the others. The Texas media market is the big prise, and, they would not have it without UT. Baylor tried to worm their way in, but, Cal and Stanford would have none of that. Basically, no Texas, no expansion.
Goes to show that there's multiple parts to the puzzle and that the conference commissioner doesn't have free reign.