I don't see how housing could cause a net migration away. The number of houses keeps going up. Unless you think that house inventory is shrinking (because growth of vacancies, etc outpace construction) at most housing prices should just determine who lives there.
I think likely the number of people living in existing housing stock is going down. I read somewhere that more than half of the rent controlled 3 bedroom apartments in San Francisco are occupied by a single older person (why leave your $1500 per month 3 bedroom apartment?). I've noticed that the single family home neighborhoods I've lived in have gone from 1-2 parents and 2-3 kids in the house to older couples or single people living in the house. And it's not just people that stay due to prop 13 -- when houses go on the market they often get bought by single people.
This is a good point. I’ll also add that California is not one big city. There are parts that are doing really well economically, and other parts that are doing terribly. Housing may be somewhat cheap on those economically deprived areas, but they’d be cheaper still in other states with better job prospect. Or, someone who grew up in California may end up leaving the state because their chosen career path wouldn’t allow for them to ever purchase a home here.
Though I agree with you about housing, if you are making an argument for bureaucracy you'd probably assign bureaucracy as the cause of a large portion of high housing costs as well.