"California has seen negative outward migration to other states for 22 of the last 25 years."
Obviously the Bay Area does not have negative outward migration, or the traffic and housing issues would be solved.
Another interesting quote cites a man inexplicably commuting from SF to the East Bay which is not something you'd do if you were trying to optimize your housing costs.
A third cites a woman and her sister moving from The Villages in SJ to Dayton, Ohio. Not mentioned is the fact that The Villages is a retirement community on a golf course (you have to be over 55 to live there).
According to census estimates, California had a natural population increase of 1,332,394 (births - deaths) from April 2010 -- August 2015. In that same period it had a net immigration of 568,884 people, consisting of +834,999 international and -266,115 domestic.
On the other hand, when you look at the San Francisco bay area metropolitan region, you'll see that there's no domestic exodus and a net immigration of 274,598 people over the last five years.
[http://factfinder.census.gov/bkmk/table/1.0/en/PEP/2015/PEPT...]
So, yeah, with a little over ~90,000 new people per year in the region, the picture looks very different than the one the article was trying to paint.