Or it could be that there simply is a dearth of FF caliber teams but 4 teams have to make it.
I enjoy PAC12 wbb games but I think that among the P5's it is the best of a not so great group. Another point about all those FF's is that the top seeded PAC12 team (either a 1 or 2) gets to stay out west EVERY YEAR. The West regional is always the furthest site for any team east of the Mississippi or in Texas so a west coast team seeded as the 4th best or 8th best still gets to stay in the west and gain the home crowd against any eastern team often getting to play in a familiar arena. A significant edge and responsible for some of those 5 teams making it there.
With respect, I feel like this analysis is really short on facts, and its claims don't actually fit the data. Here's the data for the past 5 tournaments:
In 2015, no PAC-12 teams made the Final Four. #4 Stanford was the auto-bid and was sent to Kentucky, #3 Oregon State was the only PAC-12 team to be in the West region (Spokane) and was rewarded with a second-round game against a dangerous #11 Gonzaga that upset them.
In 2016, #7 Washington got to the Final Four by beating #4 Stanford in Kentucky. #2 auto-bid Oregon State was rewarded for its conference title by having to upset #1 Baylor IN TEXAS to get to the Final Four.
In 2017, Autobid #2 Stanford upset #1 Notre Dame in Kentucky, a state which borders Indiana...
In 2018, no PAC-12 made the Final Four. 2/3 Elite Eight teams (#3 UCLA and #6 Oregon State) got there by upsetting higher ranked teams back East (UCLA beat #2 Texas in Missouri, one state over from Texas, and Oregon State beat Baylor in Kentucky).
In 2019, #2 Stanford was the auto-bid and was reward with a trip to Chicago against #1 Notre Dame (very close to a home game for the Domers). #2 Oregon got to stay in the Portland regional. That's probably the only game in all five season where region significantly benefited a PAC-12 team in an unfair way (i.e., the lower seeded PAC-12 benefited from geography - and even there, I think most people thought Oregon was a better team than MSU and they only ended up #2 because Stanford edged them in the PAC-12 championship game).
I remember one year when Duke and I assume Stan were contending for the last one seed. They gave it to Duke and the Tree fans were livid. I asked them if they would be happier if they were the one seed if it meant playing in Durham, which is what Duke was faced with. Not one of them had an answer. Stanford was going to be in the west regional no matter what and whether it was a a one or two made no difference. (Stan beat Duke in the E8)
I don't know what year you have in mind, but the last time this happened Stanford was the auto-bid and a #1 seed with a 31-1 record and Duke was a #2 at-large that went 24-5. I'm pretty sure Stanford deserved the West #1 seed over Duke. If you're remembering a different year before 2012, then you're talking about the PAC-10 era, and therefore not the era any of the rest of us is talking about, which is the past 5-6 seasons.