USC: Add any of the Big 12 schools and we're leaving.
PAC: Ok, we won't add anyone.
USC: We're leaving anyways
I hate to say it but USC played the conference and left everyone else in a really bad spot.
Waaay oversimplified.
The conference played itself and started doing so years ago.
First, they pissed USC off years ago. Then, instead of working to repair the relationship, they just continued to do stupid shit that just made things worse. Costing schools millions of dollars in revenue.
They completely fucked up the PAC 12 Network by making it 7 channels instead of 1. So, if someone in SoCal wanted to watch a team from the PAC North that was on the PAC 12 Network, they had to pay for that extra channel. Then they couldn't get hardly any cable or satellite companies to carry it. With Dish, for example, I got the SEC and B1G Networks as part of my basic package, but not PAC 12.
They also de-emphasized football to promote "Olympic sports". So those who actually could get the PAC 12 Network got more Olympic sports than football...even during football season.
They also fucked up by locating their offices in the Bay area rather than LA (the 2nd biggest media market in the country).
Those, among other reasons, are why the conference couldn't get tv deals on par with other P5 conferences, particularly the SEC and B1G.
Everyone knows that when it comes to generating revenue...football is king. It's the cash cow and virtually every other sport is paid for by football. If memory serves, the only non-football sport at USC that doesn't require some form of assistance from football is men's basketball. It's the same at virtually every school that has a football team.
USC is/was the only blue blood football program the conference had. They pissed off their only blue blood in the most important sport, then de-emphasized that sport, then fucked up the conference network and couldn't get good tv deals...and people wonder why USC wanted to gtfo.
As for the thing with Big 12, I forget what it was exactly, but there was something with the GOR where USC had to keep their plan to leave quiet and couldn't announce their intention until they did. They literally announced it the first day they could.
Even the above is an oversimplification but provides a lot more context.
TLDR: The PAC 12 played itself and deserves everything that is happening to it. Especially the schools who kept supporting Larry Scott for years after any serious conference would have told him to fuck off.