There is plenty of good talent in California alone to build national champions level teams each year. Schools across the country still recruit the west coast for a reason... I see a couple issues with west coast talent/PAC10 schools:
1) The universities in the PAC10 have not kept up with investments... in coaches, support staff, etc. The best leave or take jobs in other locations.
2) California seems obsessed with 7x7 camps. Not sure those are the best way to develop football players. I do believe the kids in the trenches are not as developed as those in the south (technique wise..)
3) In the 90's kids who came from Cali to UNL were some of the most successful in the program. Recently, they have brought a lot of attitude and not as much work. Not sure if that is more of "who" UNL recruited or a change in expectations by kids out of HS. I'd be interested in hearing if that is more universal. I just have this sense that HS rules in California are setting a different expectation on hard work compared to kids from other parts of the country. Again, it could be who riley recruited...
4) Sports are an "and" on the west coast. They frankly have more things to do that a kid growing up in Iowa. I hated that comments when people said "there is nothing to do in Nebraska" but there are fewer distractions. It is much easier to stay dedicated.
So I kinda disagree with all of these to varying degrees. With the talent part, that's true, but it's also a state with at least three times as many people as 46 of the other states. But it's also surrounded by more talent poor states, which makes it saturated in recruiters, much like Atlanta.
1. The argument about investments in perhaps in part the case, but I think it's also a set of departments that have all had their run of issues. USC has bumbled at the top for a while, despite pole position, and stumbling into Carroll covered a lot of ills. UCLA has been mostly OK with occasional bursts of pretty good. Cal is most often a mess, and Stanford is a private school that had been above its station for a while. Now some of all that I think ties into point 4, because there's less insane boosters pouring in money and demanding crazy things, which is weirdly a net good most often. There's no one to be mad you're fumbling around.
2. I live in the south. We're drowning in 7-on-7 teams. Florida is full up of them. They go to their things, linemen go to their camps. It's a good tool because practice tends to feed into games, and throwing is a skill that is super hard to build in games on lower levels. There may be some problems, but the 7-on-7s probably have little to do with it. (It's been a while since I looked into HS football in CA, but it used to strike me as more I-form/pro-style heavy than other places, though by now, the spread is probably king most everywhere)
3. Guessing that's selection bias. The kids you can get to come to 90s Nebraska were probably different than the ones Riley could sneak out. And he was already used to sneaking out second-tier guys at OSU.
4. This might be true, and it's certianly not a cultural staple the same way, though it's not like the west doesn't produce gobs of players.
The one thing I think is underrated is TV. Every game a P5 plays is to some degree national. For all but one conference, you should be able to get every game on at least an iPad anywhere. If you look at Clemson the last year a Western team won a title, they had three ESPN/ESPN2 games. One TBS (?). Three ABC, which I’m thinking was more regional than national, but occasionally national. Two Jefferson Pilot (regional). Two not on TV. If I live in Sacramento like one of their five-stars, I’m getting 5-6 out of 11 maybe. The only conference with an issue it the Pac-12, which you can solve with the right provider, but is more of a pain in the ass.