the Big 12 were to add Utah, Colorado, Arizona, and Arizona State to get to 16, that makes for a very strong conference top to bottom.
It’s more likely that happens than the PAC 12 pilfering the current or future Big 12. Because if the PAC 12 lost its 4 California schools or two of their CA schools plus Oregon and Washington, there really isn’t a big incentive for Big 12 schools to jump to the PAC 12 at that point. The Big 12 is the stronger conference with more leverage in that scenario.