IF SDSU does decide to pay up now though, they lose all of their negotiating leverage with the PAC. They could opt out now and pay the $17M buyout, but since the PAC doesn't have a contract yet, and they're talking about doing differential payments between the different schools (More to Oregon and UW), then they may end up only getting like $10 million/year offered to them. So if they're getting 5-6 now, in the MW, it would take 3-4 years to break even from what they're getting now.
IMO, they should still do it, as should UNLV if we have the chance, because that would include us in the conversation for P5 schools, regardless of how long you've been in it. It makes you more attractive if the Big 12, or other schools try to put together conferences across the entire country.