First, I think he was talking about Title IX and football schools. That makes a big difference for the women's sports.
Also, in the past few years, the WCC has looked at schools like UCSB, Denver, UOP, and Seattle. They decided that they would not help the conference. Instead, you are just splitting the revenue pie with another team without bringing more in.
Adding BYU, without a doubt, brings in more money and more interest to the WCC. I am not sure about Air Force, but they are a school of national and international interest, so maybe.
Does UCSB bring that to the WCC? UC San Diego/ Davis/Riverside, etc add nothing. They don't want to add schools just to add schools.