https://en.wikipedia.org/wiki/List_of_supermarket_chains_in_...
https://www.kroger.com/search?query=salt&searchType=default_...
And just Food Lion alone has probably half a dozen to a dozen different salt varieties on the spice aisle.
I'm sure there are places in the US where choice is more limited, but that's the thing about a country of the size of the United States... you can find all kind of scenarios in different regions.
I've lived in a few overseas countries and consumer choice is absolutely limited. As a result you see a lot of people trying to import things they want that they can't otherwise get in their country.
If your hobby is cooking, good luck getting Arabic food ingredients in say Vietnam.
But in the US? If your own city doesn't have a store that carries them, you could easily order them online for next day delivery.