All I am saying is both leagues are about equal so why leave
The Big 12 is more stable for Arizona or Utah because they already know that the B1G, SEC, ACC don't want any of those schools. They all tried a year ago and got rejected. Ironic that it works this way, but the Big 12 is much more stable for this reason.
If you stay in the Pac-12 because it's about equal then you might get nuked when Washington and/or Oregon bail on you. For the B1G, for the SEC, maybe for the ACC, maybe even for a sweetheart uneven revenue sharing deal in the Big 12. It's riskier. Big 12 is a safer play to stay at the table.
Somebody in the Pac-12 right now is likely to get demoted out of the P5 (or P4 once that league collapses). If you take the Big 12 invite now you guarantee that it's not you. That's extremely attractive considering the only schools guaranteed to not get demoted are Oregon and UW. There are scenarios where any of the other 8 end up in the Mountain West.