> Why do crops need to be grown in California or 'shipped' to China? Can't these crops be provided by other states in the U.S. that are more conducive to farming?
If they could, they would.
> It seems California is not a great state for farming, and was engineered to be suitable.
No place is a great place for modern farming, which requires considerable man-made infrastructure in any case. But in terms of things that you can't easily engineer around (except, recently, fresh water within a convenient collection area) California is a very good place for farming.