12 years? Aside from the Aaron Rogers / Beastmode era, Cal sucked prior to 12 years ago, too.
Keeping Shaw didn't make Stanford irrelevant. Having an administration that prioritizes education over football + the new transfer portal rules, made Stanford irrelevant. They have had exactly 1 undergrad transfer during the Transfer Portal era and 4 or 5 total transfers since 2015. That makes it nearly impossible to compete with schools than can just plug in guys from other schools. Plus, they don't bend the academic rules like 95% of the football programs out there.
If you can ball, having a 900 SAT and majoring in finger painting can get you into USC. Not Stanford.
Stanford and Cal were minor players at best. The PAC failed because its' most valuable program, USC, had not won an MNC in nearly 2 decades, which devalued the appeal of the PAC. Oregon, while better on the field, is worth far less from a media rights standpoint and they couldn't get it done either.
Another way to say that, is that since USC has sucked for +14 years, they devalued the PAC and ended up leaving because of it. Kind of like shitting in your own bed and then finding somewhere else to lay down.