I wonder how many of these people moving are taking advantage of remote work and keeping their same jobs while enjoying lower living expenses. I heard that facebook is downgrading salaries of people who do this based on where they are moving to.
That said, I imagine the majority are hardship and/or people just escaping the cost of living and traffic. If I paid through the nose to live in San Ramon or the San Fernando valley only to spend hours in horrendous traffic per day commuting, I'd probably be over it too.
I love where I live and will probably live out my career here, although I don't see myself retiring here. I could make it work, but if I have to live like a monk, I'd rather stretch my dollar elsewhere. Will probably split my time between 2-3 places with maybe 3-4 months/year in the states.