I agree with Frost that we need to recruit wherever the best players are that will fit our system and want to be Huskers. Both those requirements are critical.
California has not been as fruitful for NU as other places east of the rockies. I would suggest that distance and travel challenges for players and their families are a big part of the problem.
I don't think we 'need' to recruit the west coast to find plenty of talent but there is no reason not to recruit out there UNLESS the recruiting time and resources become spread too thin. The coaches spend huge amounts of time and money traveling, etc. so it only makes sense to focus or concentrate on geographic regions where they get the most bang for the buck. If you just stay east of the Rockies, you would still have literally thousands of excellent prospects to select from.
However, we've had some good players from all over the country over the years. I would suspect the biggest single factor in having success in recruiting players from one or another region directly correlates to the relationships between coaches and the particular schools, coaches, families, etc. I would be shocked if one doesn't find that it is not so much the where but the who of the matter.
They need to really focus on the legacy recruits and utilize any and all possible family ties, coaching connections, etc. No doubt they are trying everything possible. I am sure they are leaving no stone unturned - their jobs and futures depend on it.