The brain drain of Cali has already been mentioned, and that guns are but one piece of a much larger mosaic. Why live in a rediculously high tax state with rediculous land values, and rent prices, when you can get a much better deal in no income tax, no corporate tax, Uzi legal Nevada right across the border?
Even people that don't own guns or are ambivalent probably still want an easier life.
As Shooter 94? pointed out, average house, 600K
Average monthly rent: 1K
Average hourly salary for unskilled labour: 7-10 bucks an hour. No wonder people make up for rent by putting 4-5 illegals in their basement. In fact, the illegal problem, combined with manufacturing being outsourced caused this problem.
The illegals who come in droves to do jobs Americans won't do for slave wages need a place to stay, which in turn drives up costs of housing, untilities, insurance, etc.
These illegals do jobs which would pay $15-$20, and make these jobs only worth $5-$10 per hour.
No one can live on that and afford the homes around there.
Unfortunately, this leads to calls for ever greater taxes and welfare to make up the slack of cut wages and benefits, which makes employers want to go out of sate, and "offshore" earnings (whether literally, or just out of state).
Such welfare is not without price, and so you give up more privacy to the tax man, more property rights to the government, and your guns to the police power to try to regulate urban sprawl, and higher rent, expanded welfare, and increasing crime amongst the illegals, and other unsavory sorts.
Over time, this will go to the rest of the country unless we can nip it in the bud.
(Sorry, rant off)