Suburban and housing costs in California are very high by national standards. Is your argument that the people who are moving out of California overwhelmingly non-native Californians?
Eureka is charming enough, but it has no specific attractive force over any other (very) small coastal city where the next-larger city is many hours' drive away. Compare to Crescent City, or southern coastal Oregon.
So yes, you're still in California up there, and housing is less expensive. But there are no jobs (WFH tide floats all boats), and it isn't the California that most people are looking for. See also: Bakersfield.
Sure beats Crescent City though.
But for every buck you save, you lose an hour of your life to our terrible transportation infrastructure. Twice the house, four times the drive. It's why the housing price equation is as unbalanced as it is here.
What does Eureka have (appart for nice nature)? How much does one has to drive to go to an airport that can fly directly to Europe or Asia? If your local business closed, how long and how much would you have to drive to find another job?
Commanding a mid-level metro prices, without the economy vibrancy of one, is sheer overpricing. And maybe that's why so many locals are leaving. (the influx is usually immigrants, which are more willing to put up with crappier conditions).
And you're right, maybe Raleigh is a better choice. Or maybe Minneapolis. Or perhaps Boise, or any number of other mid-size capitol cities. But they aren't California.
The opportunities available in Eureka are not the same ones available in the Bay Area (although it's likely gotten better). I suspect they don't even stack up to Raleigh favorably. Eureka is much smaller than many bay area cities, and more importantly, is isolated, so it feels much smaller than even the ones that it is similarly sized to, as once you leave Eureka, you're not immediately entering another city of the same or larger size.
In fact 500,000 of them without health insurance are looking encouragingly at a possible medicaid expansion 11 years after the ACA passed.
CA is overpriced by a long shot
(In fact Eureka is fairly centrally located on the coast, which is kind of cool, too. I’d want to live in Arcata instead because less tweakers. But Arcata isn’t directly on the coast, so you can’t really compare them)
As for the populace... they don't call it Eutweaka for nothin
Eureka can be overpriced while the overall thesis remains carefully constructed malarkey. NC has grown by 300% in the last century while CA has grown by 900% in the same period. More recently NC has grown at about 1% per year over the last decade. California grew similarly over the same period until 2016 when it started to slow down. Its barely a blip in the graph and needs no complicated explanation.
They must have started renting that house at least 10 years ago and had a landlord who never rose the price. Because rental prices for large houses are $2000+ (Eureka/Arcata) or $1800+ (McKinnleyville) now.
It’s not that an overwhelming percentage of people leaving recently moved in, but they do represent a larger percentage of people moving out which is normal.