This seems like the norm in the US, whereas it was quite easy to get a job with a company in a more lax jurisdiction. I wonder to what degree it correlates with employee protections (if there is a strong correlation, one would expect French companies to have the most demanding interviews, since it is almost impossible to fire someone).
The interviews are harder or more abstract and longer in California. It feels like no one is sure why they are hiring so they prolong the hiring process as a safeguard.
Yet, California has had plenty of people moving in to the state from elsewhere, enough to cause an acute housing problem in some areas. Something feels off in your analysis.
Speaking from someone not in California but who has remotely interviewed with companies across the globe.
No one does 4, 5, 6 interviews if they know what they want and are worried about losing them. No one is worried because the candidate pool is so large and the position doesn't really need to be filled.
> one would expect French companies to have the most demanding interviews, since it is almost impossible to fire someone).
In my experience, it's not that hard. You have up to six months to fire the new hire for whatever reason you like. They can also leave during this time, of course, but people have a tendency not to.