The problem is you could replace SDSU with SMU or BSU, and it's pretty much the same situation. Any of these would likely take a similar deal, and all have limited media value. Any difference in media value between them is in the absolute margins, and won't matter.
Unless the PAC would simply rather die as a conference than elevate any G5 other than SDSU, there's no situation where SDSU's availability will impact the PAC's survival as a power conference.
You can? You think the PAC views adding BSU the same as adding SDSU? No.
You think AZ thinks the same about coupling with BSU as they do SDSU? no.
If the Big 12 causes those schools to get added to the PAC because SDSU thinks it can go to Big 12, job well done.
If nothing else, this is about driving up the cost of adding to the PAC. If there is a market for SDSU, the PAC can't revenue rape them as badly.