You have your points JP. But lemme clarify to each one a bit:
ONLY the Big West would be stable IF Hawaii leaves the Big West and join the Mountain West for all sports ...
You're right. It would be best for the Big West to be a one-state regional conference. But it need more schools that are either Cal State-________ or UC-________ and Hawaii must NOT be in the conference. Ironically, the Rainbow Warriors are in the Big West because they had no choice to find a home for Olympic sports after leaving the WAC.
One school that might leave doesn't make a conference "unstable." A conference is stable if they have no real concern of NEEDING to go out and add new members in order to protect their place in the national landscape.
The BWC can't be unstable WITH Hawaii and STABLE without Hawaii. They're stable either way. When Hawai'i HAS to join a FBS conference for all sports, they will. The BWC and MWC both know it. And the BWC is totally stable because they have EIGHT members with NO WHERE ELSE TO GO.
Poly and Davis can't afford to upgrade their football programs to FBS. They have a FCS home in the Big Sky;
The Big Sky has 12 full members and the markets of Davis (covered by Sac State) and San Luis Obispo (#167) are not factors.
Adding UCD & CP / Joining the Big Sky only adds travel expenses to all 14 schools; and doesn't increase revenue at all.
The other six have even less options.
You seem like a really bright guy, but in reading your posts in threads I think you're taking a "looking down" or "outsider" approach to conference realignment. Looking down at all the schools/conferences on a map, it's really easy to shuffle schools around and re-draw affiliations for symmetry, rivalries, geography, etc. (with probably awesome results).
Looking down, CSU Bakersfield and Sacramento State "belong" in the Big West more than they "belong" in the Big Sky or WAC.
You have to look at these situations from street-level or within each school and conference. Each party is going to make decisions based on their own self-interest. Geography and symmetry always lose to revenue added and expenses saved. Bakersfield doesn't give the Big West anything, hence no invite. They MIGHT if they came with UC San Diego, but that's on hold. I'm sure the BWC would love to add Sac State and UC San Diego for 12, but Sac State isn't interested.