They have leverage NOW, because moving now involves some risk regarding the state of the future PAC-12. If the rumored four want to move, then now is the time. If they wait until after additional B1G departures, then they will lose that leverage as staying in the PAC isn't really an option. The Big 12 could decide that doubling markets in AZ and UT is less desirable than grabbing a new school in California or Washington. They could decide that two between Colorado and Arizona is more additive than four. There is a lot of risk in waiting if you are a Utah/ASU/Arizona.