There are so many factors that need to be taken into account that it’s a moving target. I don’t think that SoCal will ever be a ghost town. But I do think that many of the positive reasons for moving/living here or opening a business here are decreasing relative to all the negative reasons. Firstly, California is not a business-friendly state. Ask any business owner. There are so many regulations and costs (ex. worker’s comp) that it’s just not as enticing as a state that cares more about employers. A good, recent example of a business leaving the San Diego area is the Buck Knife factory. They packed up and moved to Idaho (I think) because it got too expensive to operate in San Diego. I am a small business owner here and I actually incorporated my biz in Nevada. I am also considering outsourcing some of my labor elsewhere, such as India. You want to talk about educated, motivated people? India workers are some of the best and they speak English very well. No, I’m not Indian, either. As for the motivated Mexican worker, the first generation are usually highly motivated, but I have seen first hand that the next generation can become Americanized and isn’t as motivated as the first.
In terms of how population growth is affected, it all depends on the type of population you are talking about. Immigrant population can be a factor in housing because many immigrants (particularly Hispanic) that come here come from nothing and don’t have much to lose. Living in an undesirable city or town is actually an upgrade for them. You are right in that both sides of the argument can’t be argued. I made an earlier post where I hypothesized that illegal immigration will have a net increase effect on home prices. But this may not be the case if the increasing population is not able to afford the home prices here.
Who knows all the reasons why people move? The main reason is to simply make a better life, whatever that constitutes. Many middle-class Californians have (and are continuing) to leave the state for greener pastures. Businesses are doing the same. I don’t have hard numbers to back this up, but I believe it to be true. The American dream is simply more attainable and less taxing elsewhere. If the only affordable housing in SoCal is way out in the desert, why not go to Arizona or Nevada? The desert is much cheaper there.