Because the economic situation in Orange County reflects that of the whole country. Right, ok. That’s like judging the French economy by the Riviera or the New York economy from the Hamptons.
Also, if you correlate home prices to average incomes, you’re ass-u-meing that all people buy homes at the ideal value-to-income ratio. I suspect that the lower 30-40% of incomes in Orange County aren’t buying homes any time soon, and thus the home price numbers are skewed towards the wealthier end of the spectrum.
Kind of like in NYC, where only 30-40% of so of residents own their homes.