I thought they'd felt out of place for a long time and the scare was just the little nudge they needed. I think they would've liked to join the pac 12 (10 at the time) but couldn't because the league was looking to add 2+CCG, without Utah's emergence, idk that they ever get their pac 12 invite. Regardless, they didn't want to be here.
A professor of mine at ISU was in Boulder before he came to Ames.
He told me that Colorado going to the Pac-10 was a multi-decade ambition of theirs. They felt they were a better cultural fit with the Pac-10 schools than with the Texas schools and wanted to be rubbing shoulders with academic titans like UCLA, Berkeley, Stanford.
They just kept getting shut down because the Pac-10 wanted an even number and there were no viable partners to go with Colorado. The Pac-10 took Colorado with the full expectation they would bag much of the Big 12 South, probably something like this...
Pac-16 West
---
California
Oregon
Oregon State
Southern California
Stanford
UCLA
Washington
Washington State
Pac-16 East
---
Arizona
Arizona State
Colorado
Oklahoma
Oklahoma State
Texas
Texas A&M
Texas Tech
They took Colorado with the expectation they would land the other five. When they did not, they took Utah as the "least bad" option to even things back out. I bet if they knew they were only going to get Colorado and Utah out of the deal, they would have stayed at ten.
It is my understanding the California schools turn their nose at Utah (and for obvious reasons). BYU has a snowball's chance in heck of ever ending up in that conference.