SoCal could easily get whacked 50-60% in SFH prices. It depends on how badly the economy performs / the resulting job losses / number of foreclosures / amount of available inventory / etc-yada yada yada.
That article is referring to the national home market and many cities did not have the ridiculous run-up in house prices that CA experienced.
I have a friend who bought a nice townhome in SD in 1997 for $180k. He could have easily sold it for $500k-$520k in early 2005 and I encouraged him to do so but he decided to wait. Today, it’s only worth around $360k and the value is falling every month. I would not be surprised to see his townhome (1800 sq ft / 2 car garage) drop all the way to $200k before things clear up, primarily due to the number of SFH / Condos / Townhomes that will be on the market as more & more owners default on their loans.
Time will tell who is correct.