UT Austin would never be willing to take a back seat to the likes of USC and Oregon.
The Pac invited Colorado so they could tell the Texas legislators, "Sorry, no room for faith-based Baylor," really, truly having the hubris to think Texas would join them. Then, when their ego came crashing down to the tune of a resounding Texas NO, they had to scramble, tail between their legs, to find a 12th to satisfy the championship game requirement. They swallowed hard, swore under their breath, and invited Utah.
And somehow the Yewts' heads have been huge about it ever since.