Earlier quoted context omitted.
The SF Bay Area is hardly an outlier. There may be more specialty grocery stores here, but the large supermarkets where most consumers buy most of their food are the same as anywhere else. If you compare a Safeway in Mountain View, CA to a Publix in Daytona Beach, FL or a Kroger in Toledo, OH there isn't much difference in the products available.
I hope that you recognize that your casual-outsider evaluation of the assortments of these stores is deeply flawed and not based on actual data. If you think about it even just a little bit, you'll recognize that it wouldn't make sense for a supermarket in one of the highest median income cities in the country to have assortment parity with a chain targeting cost conscious shoppers. The devil here is in the long-tail…
Instead of making things up you can just go look. Many supermarkets have online ordering now so you can see exactly what they stock at each local store.