I live in California and go to Arkansas twice a year to visit family. Their housing is not that cheap and their groceries are about the same. The real difference is the costs of their utilities.
Haven’t lived in CA in ten years, but I suspect utilities have gone up bunch.
I’ve always thought the cost of living scales are misleading. They imply all or most items are that much higher, and they’re just not.
When it comes to housing, the comparison is always between a similar house in AR and CA. CA housing prices vary even more inside the state than to other states. If you want to live in the “nice” parts of CA and aren’t wealthy, you will have to accept a much less elaborate house.