...the strongest bet for a P5 invite for BYU and so we wanted them to survive while we wanted the PAC (and Utah) to bear the brunt.

But it was never going to be the PAC, simply as a result of geography. USC, UCLA, Stanford, Oregon, Washington all play at a high enough level (either historically, currently, or both) and bring in enough money/respect that they are going to be included on that have side of any have/have-not break. - (The rest of the teams - Arizona, Arizona St, Colorado, Utah, Cal, Washington St, Oregon St could end up on either side depending on how things shake out)

And trying to split those institutions among different conferences just becomes a logistical nightmare, given the geography. You're not going to have Oregon/Washington in the Big 10 with Rutgers and Penn State. Or USC/UCLA in the Big 12 with West Virginia. Simply put, there's no simple way for the PAC12 to break up. The closest you could get would be a merger with another league (similar to creating the MWC) where the majority of the PAC would stick together and merge with another league, but that would still leave the new league as the successor to the PAC more a breakup of the PAC.

On the other hand, the Big12 is surrounded by alternative conferences. It's much more realistic for
Texas/Oklahoma to go to the SEC (giving them 16)
Kansas/Iowa St to the Big 10 (giving them 16)
West Virginia to the ACC (giving them 16 with Notre Dame - or UCF if ND stays independent)
Texas Tech/Oklahoma St to the PAC12 (giving them 14, with the last two spots to be filled by some combo of San Diego St, UNLV, Boise, BYU, TCU, Kansas St)

And just like that, the Big 12 is left with between one (Baylor) and three (Baylor, TCU, K State) teams, all of which likely find homes in some combination of G5 conferences. If there ends up being 4x16 and Notre Dame joins a conference, then I think BYU will ultimately have to end up joining a conference as well. Maybe a MWC with BYU and Baylor added? Or BYU, Baylor, TCU added if one of San Diego St or UNLV gets the PAC12 spot? Or maybe Baylor goes to the AAC. K-State would similarly be able to go to any of MAC, ACC, MWC