At this point, it's going to be the PNW "State" schools taking in roommates because the mansion is empty and falling apart but the address still looks fancy.
UCLA/Stanford double alum here: the damage is done. The California schools belong together and UO/UW are great acquisitions for the B1G. This was the obvious move as soon as the LA schools jumped and I assume it was part of the original negotiations (with USC).
Why? As a UW fan I fucking hate this. I want to watch my team play teams in my region. I don't care about midwest college teams. I'd rather have stayed in a decimated PAC 12 with our boys WSU out of principle.
I'm not terribly surprised, as the Big 10 wants that Stan/Cal research money, and will be able to get all 4 schools with reduced payouts. However I wonder what this means for FSU and the ACC? This almost surely means the Big 12 will take 4 corners schools, but are they willing to add more if the ACC crumbles and Pitt, NCST, GT, VT, UL, etc are on the table?
Stanford and Cal would be nice, they are an outstanding academic fit. But I give the FSU-Clemson rumors more credibility. Stanford is rumored to be insisting on Notre Dame, and ND has said no to the B1G multiple times now. That ship has sailed.
I don't expect this to be resolved before the Big XII 2024 lineup is finally set, but this might push the remaining four corner schools to move more urgently. If the Big Ten is talking about it now, then there was probably a lot of weight to that "blood on hands for delivering the killing stroke to the Pac" argument. Still doesn't mean it will happen, but it would leave the Pac-12 North in a tight spot if it didn't. I'm sure the B1G's preference is to integrate two schools at a time, but if they have any interest in getting any more schools for a discount, they most likely will.
A little shameless promotion: There's a way to "fake" flair, at least on Mac/PC, if you know greasemonkey. Head to this thread, post what you like, and I'll centralize the list, formatted for the script I use.