I thought they took Colorado anticipating they were about to raid the rest of the Big 12 South and create a Pac-16 super-conference built around the academic prestige of the likes of Stanford, Berkeley, UCLA, and Texas paired up with the athletics brand and money of Texas, Texas A&M, Oklahoma, Southern California, and Oregon.
Merging California, Texas, and Nike into a single conference... sounds like it would have been powerful.
But then it didn't happen, and they were left holding the bag. They did not want to go on with an odd number of teams, so they took Utah as the best MWC option remaining to even themselves up at a Pac-12.
This plan...
EAST = Arizona, Arizona State, Colorado, Oklahoma, Oklahoma State, Texas, Texas A&M, and Texas Tech
WEST = Cal, Oregon, Oregon State, Stanford, UCLA, USC, Washington, and Washington State
...looks a lot better than what they actually got.